diff --git a/runtime/include/discord_presence.h b/runtime/include/discord_presence.h
new file mode 100644
index 0000000..3bd6025
--- /dev/null
+++ b/runtime/include/discord_presence.h
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+// Host implementation of Dolphin's /dev/dolphin Discord contract. The guest
+// sends only strings and big-endian integer fields; the IPC wire protocol is
+// owned here so translated game code never needs host SDK headers.
+namespace DiscordPresence {
+
+struct Activity {
+    std::string details;
+    std::string state;
+    std::string largeImageKey;
+    std::string largeImageText;
+    std::string smallImageKey;
+    std::string smallImageText;
+    int64_t startTimestamp = 0;
+    int64_t endTimestamp = 0;
+    uint32_t partySize = 0;
+    uint32_t partyMax = 0;
+};
+
+void Initialize(const std::string& basicClientId, const std::string& basicTitle);
+void SetClient(const std::string& clientId);
+void SetActivity(Activity activity);
+void Reset();
+void Shutdown();
+
+} // namespace DiscordPresence
diff --git a/runtime/include/runtime_config.h b/runtime/include/runtime_config.h
index c028a2b..f7b0a4c 100644
--- a/runtime/include/runtime_config.h
+++ b/runtime/include/runtime_config.h
@@ -53,6 +53,11 @@ struct RuntimeUserConfig {
     std::optional<bool> audioMixWorker;
     std::optional<bool> attenuateMusicWhenMediaPlays;
     std::optional<bool> networkEnabled;
+    std::optional<bool> discordPresenceEnabled;
+    // The application ID of the WiiCompiled Discord application. This is only
+    // used by the base product; Retro Rewind supplies its own ID through the
+    // standard Dolphin /dev/dolphin interface.
+    std::optional<std::string> discordClientId;
     std::optional<std::string> nandRoot;
     std::optional<std::string> dvdRoot;
     // The one canonical Retro Rewind installation, owned and updated by the frontend. Setup records
@@ -286,6 +291,12 @@ inline void EnsureConfigFile() {
               "mix_worker = true\n\n"
               "[network]\n"
               "enabled = true\n\n"
+              "[discord]\n"
+              "# Rich Presence talks only to a locally-running Discord client.\n"
+              "# Retro Rewind supplies its official app ID automatically. Set this\n"
+              "# to WiiCompiled's Discord application ID for basic base-game presence.\n"
+              "enabled = true\n"
+              "# client_id = \"123456789012345678\"\n\n"
               "[paths]\n"
               "# dvd_root = \"D:\\\\MarioKartWii\\\\DATA\"\n"
               "# nand_root = \"D:\\\\WiiNand\"\n"
@@ -418,6 +429,8 @@ inline RuntimeUserConfig ParseConfigDocument(const toml::value& document) {
     config.attenuateMusicWhenMediaPlays =
         FindConfigValue<bool>(document, "audio", "attenuate_music_when_media_plays");
     config.networkEnabled = FindConfigValue<bool>(document, "network", "enabled");
+    config.discordPresenceEnabled = FindConfigValue<bool>(document, "discord", "enabled");
+    config.discordClientId = FindConfigValue<std::string>(document, "discord", "client_id");
 
     config.nandRoot = FindConfigValue<std::string>(document, "paths", "nand_root");
     config.dvdRoot = FindConfigValue<std::string>(document, "paths", "dvd_root");
@@ -815,6 +828,14 @@ inline std::string RetroRewindRoot(std::string fallback = "") {
     return Get().retroRewindRoot.value_or(std::move(fallback));
 }
 
+inline bool DiscordPresenceEnabled(bool fallback = true) {
+    return Get().discordPresenceEnabled.value_or(fallback);
+}
+
+inline std::string DiscordClientId(std::string fallback = "") {
+    return Get().discordClientId.value_or(std::move(fallback));
+}
+
 inline const std::vector<std::string>& OverlayRoots() {
     return Get().overlayRoots;
 }
@@ -871,6 +892,9 @@ inline void LogLoadedConfig() {
             if (config.networkEnabled) {
                 std::cout << " network_enabled=" << (*config.networkEnabled ? "true" : "false");
             }
+            if (config.discordPresenceEnabled) {
+                std::cout << " discord_enabled=" << (*config.discordPresenceEnabled ? "true" : "false");
+            }
             if (config.nandRoot) {
                 std::cout << " nand_root=" << *config.nandRoot;
             }
diff --git a/runtime/src/discord_presence.cpp b/runtime/src/discord_presence.cpp
new file mode 100644
index 0000000..f312cd0
--- /dev/null
+++ b/runtime/src/discord_presence.cpp
@@ -0,0 +1,408 @@
+#include "discord_presence.h"
+
+#include "runtime_log.h"
+
+#include <algorithm>
+#include <array>
+#include <chrono>
+#include <cctype>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <mutex>
+#include <sstream>
+#include <string_view>
+#include <utility>
+#include <vector>
+
+#if defined(_WIN32)
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
+#else
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#endif
+
+namespace DiscordPresence {
+namespace {
+
+constexpr uint32_t kHandshakeOpcode = 0;
+constexpr uint32_t kFrameOpcode = 1;
+constexpr size_t kMaxClientIdLength = 32;
+
+bool IsClientId(std::string_view value) {
+    return !value.empty() && value.size() <= kMaxClientIdLength &&
+           std::all_of(value.begin(), value.end(), [](unsigned char ch) { return std::isdigit(ch) != 0; });
+}
+
+std::string EscapeJson(std::string_view value) {
+    std::string escaped;
+    escaped.reserve(value.size());
+    for (const unsigned char ch : value) {
+        switch (ch) {
+        case '\\': escaped += "\\\\"; break;
+        case '\"': escaped += "\\\""; break;
+        case '\b': escaped += "\\b"; break;
+        case '\f': escaped += "\\f"; break;
+        case '\n': escaped += "\\n"; break;
+        case '\r': escaped += "\\r"; break;
+        case '\t': escaped += "\\t"; break;
+        default:
+            if (ch < 0x20) {
+                static constexpr char kHex[] = "0123456789abcdef";
+                escaped += "\\u00";
+                escaped += kHex[ch >> 4];
+                escaped += kHex[ch & 0x0f];
+            } else {
+                escaped += static_cast<char>(ch);
+            }
+        }
+    }
+    return escaped;
+}
+
+void AppendJsonString(std::ostringstream& output, bool& hasValue, std::string_view key, std::string_view value) {
+    if (value.empty()) {
+        return;
+    }
+    if (hasValue) {
+        output << ',';
+    }
+    output << '\"' << key << "\":\"" << EscapeJson(value) << '\"';
+    hasValue = true;
+}
+
+std::string BuildActivityPayload(const Activity& activity) {
+    std::ostringstream json;
+    json << "{\"cmd\":\"SET_ACTIVITY\",\"nonce\":\"wiicompiled\",\"args\":{\"pid\":";
+#if defined(_WIN32)
+    json << static_cast<unsigned long>(::GetCurrentProcessId());
+#else
+    json << static_cast<long>(::getpid());
+#endif
+    json << ",\"activity\":{";
+    bool hasActivityField = false;
+    AppendJsonString(json, hasActivityField, "details", activity.details);
+    AppendJsonString(json, hasActivityField, "state", activity.state);
+    if (hasActivityField) {
+        json << ',';
+    }
+    json << "\"assets\":{";
+    bool hasAsset = false;
+    AppendJsonString(json, hasAsset, "large_image", activity.largeImageKey);
+    AppendJsonString(json, hasAsset, "large_text", activity.largeImageText);
+    AppendJsonString(json, hasAsset, "small_image", activity.smallImageKey);
+    AppendJsonString(json, hasAsset, "small_text", activity.smallImageText);
+    json << "},\"timestamps\":{";
+    bool hasTimestamp = false;
+    if (activity.startTimestamp > 0) {
+        json << "\"start\":" << activity.startTimestamp;
+        hasTimestamp = true;
+    }
+    if (activity.endTimestamp > 0) {
+        if (hasTimestamp) {
+            json << ',';
+        }
+        json << "\"end\":" << activity.endTimestamp;
+    }
+    json << "},\"party\":{";
+    if (activity.partySize > 0 || activity.partyMax > 0) {
+        json << "\"size\":[" << activity.partySize << ',' << activity.partyMax << ']';
+    }
+    json << "},\"instance\":false}}}";
+    return json.str();
+}
+
+class Client {
+public:
+    void Initialize(const std::string& clientId, const std::string& title) {
+        std::lock_guard<std::mutex> lock(mutex_);
+        basicClientId_ = IsClientId(clientId) ? clientId : std::string{};
+        basicActivity_ = {};
+        basicActivity_.details = title;
+        basicActivity_.startTimestamp = UnixSeconds();
+        customClient_ = false;
+        activity_ = basicActivity_;
+        ReconnectAndSendLocked();
+    }
+
+    void SetClient(const std::string& clientId) {
+        std::lock_guard<std::mutex> lock(mutex_);
+        if (!IsClientId(clientId)) {
+            RT_LOG(RT_TAG_RUNTIME) << "Ignoring invalid Discord client ID from /dev/dolphin" << std::endl;
+            return;
+        }
+        if (clientId_ == clientId && connected_) {
+            return;
+        }
+        customClient_ = true;
+        clientId_ = clientId;
+        CloseLocked();
+        ReconnectAndSendLocked();
+    }
+
+    void SetActivity(Activity activity) {
+        std::lock_guard<std::mutex> lock(mutex_);
+        if (!customClient_) {
+            return;
+        }
+        activity_ = std::move(activity);
+        SendActivityLocked();
+    }
+
+    void Reset() {
+        std::lock_guard<std::mutex> lock(mutex_);
+        customClient_ = false;
+        clientId_.clear();
+        activity_ = basicActivity_;
+        CloseLocked();
+        ReconnectAndSendLocked();
+    }
+
+    void Shutdown() {
+        std::lock_guard<std::mutex> lock(mutex_);
+        CloseLocked();
+    }
+
+private:
+    static int64_t UnixSeconds() {
+        return std::chrono::duration_cast<std::chrono::seconds>(
+            std::chrono::system_clock::now().time_since_epoch()).count();
+    }
+
+    std::string ActiveClientIdLocked() const {
+        return customClient_ ? clientId_ : basicClientId_;
+    }
+
+    bool WriteFrameLocked(uint32_t opcode, std::string_view payload) {
+        std::array<uint8_t, 8> header{};
+        const uint32_t size = static_cast<uint32_t>(payload.size());
+        for (size_t i = 0; i < 4; ++i) {
+            header[i] = static_cast<uint8_t>(opcode >> (i * 8));
+            header[4 + i] = static_cast<uint8_t>(size >> (i * 8));
+        }
+        return WriteAllLocked(header.data(), header.size()) &&
+               WriteAllLocked(reinterpret_cast<const uint8_t*>(payload.data()), payload.size());
+    }
+
+    void ReconnectAndSendLocked() {
+        const std::string clientId = ActiveClientIdLocked();
+        if (clientId.empty() || !ConnectLocked()) {
+            return;
+        }
+        const std::string handshake = "{\"v\":1,\"client_id\":\"" + clientId + "\"}";
+        if (!WriteFrameLocked(kHandshakeOpcode, handshake)) {
+            CloseLocked();
+            return;
+        }
+        if (!ReadReadyLocked()) {
+            CloseLocked();
+            return;
+        }
+        SendActivityLocked();
+    }
+
+    void SendActivityLocked() {
+        if (!connected_ && !ConnectLocked()) {
+            return;
+        }
+        if (ActiveClientIdLocked().empty()) {
+            return;
+        }
+        if (!WriteFrameLocked(kFrameOpcode, BuildActivityPayload(activity_))) {
+            CloseLocked();
+        }
+    }
+
+#if defined(_WIN32)
+    bool ConnectLocked() {
+        if (connected_) {
+            return true;
+        }
+        for (unsigned int index = 0; index < 10; ++index) {
+            const std::string name = "\\\\.\\pipe\\discord-ipc-" + std::to_string(index);
+            handle_ = ::CreateFileA(name.c_str(), GENERIC_READ | GENERIC_WRITE, 0, nullptr, OPEN_EXISTING, 0, nullptr);
+            if (handle_ != INVALID_HANDLE_VALUE) {
+                DWORD mode = PIPE_READMODE_BYTE;
+                ::SetNamedPipeHandleState(handle_, &mode, nullptr, nullptr);
+                connected_ = true;
+                return true;
+            }
+        }
+        return false;
+    }
+
+    bool WriteAllLocked(const uint8_t* data, size_t size) {
+        while (size != 0) {
+            DWORD written = 0;
+            if (!::WriteFile(handle_, data, static_cast<DWORD>(size), &written, nullptr) || written == 0) {
+                return false;
+            }
+            data += written;
+            size -= written;
+        }
+        return true;
+    }
+
+    bool ReadAllLocked(uint8_t* data, size_t size) {
+        while (size != 0) {
+            DWORD read = 0;
+            if (!::ReadFile(handle_, data, static_cast<DWORD>(size), &read, nullptr) || read == 0) {
+                return false;
+            }
+            data += read;
+            size -= read;
+        }
+        return true;
+    }
+
+    void CloseLocked() {
+        if (handle_ != INVALID_HANDLE_VALUE) {
+            ::CloseHandle(handle_);
+            handle_ = INVALID_HANDLE_VALUE;
+        }
+        connected_ = false;
+    }
+
+    HANDLE handle_ = INVALID_HANDLE_VALUE;
+#else
+    bool ConnectLocked() {
+        if (connected_) {
+            return true;
+        }
+        std::array<std::string, 5> roots{};
+        size_t rootCount = 0;
+        if (const char* runtimeDir = std::getenv("XDG_RUNTIME_DIR"); runtimeDir && *runtimeDir) {
+            roots[rootCount++] = runtimeDir;
+        }
+        if (const char* tempDir = std::getenv("TMPDIR"); tempDir && *tempDir) {
+            roots[rootCount++] = tempDir;
+        }
+        if (const char* tempDir = std::getenv("TMP"); tempDir && *tempDir && rootCount < roots.size()) {
+            roots[rootCount++] = tempDir;
+        }
+        if (const char* tempDir = std::getenv("TEMP"); tempDir && *tempDir && rootCount < roots.size()) {
+            roots[rootCount++] = tempDir;
+        }
+        roots[rootCount++] = "/tmp";
+        for (size_t rootIndex = 0; rootIndex < rootCount; ++rootIndex) {
+            for (unsigned int index = 0; index < 10; ++index) {
+                const std::string path = roots[rootIndex] + "/discord-ipc-" + std::to_string(index);
+                if (path.size() >= sizeof(sockaddr_un::sun_path)) {
+                    continue;
+                }
+                const int socketFd = ::socket(AF_UNIX, SOCK_STREAM, 0);
+                if (socketFd < 0) {
+                    continue;
+                }
+                sockaddr_un address{};
+                address.sun_family = AF_UNIX;
+                std::memcpy(address.sun_path, path.c_str(), path.size() + 1);
+                if (::connect(socketFd, reinterpret_cast<const sockaddr*>(&address), sizeof(address)) == 0) {
+                    timeval timeout{};
+                    timeout.tv_sec = 1;
+                    ::setsockopt(socketFd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout));
+                    fd_ = socketFd;
+                    connected_ = true;
+                    return true;
+                }
+                ::close(socketFd);
+            }
+        }
+        return false;
+    }
+
+    bool WriteAllLocked(const uint8_t* data, size_t size) {
+        while (size != 0) {
+            const ssize_t written = ::send(fd_, data, size, MSG_NOSIGNAL);
+            if (written <= 0) {
+                return false;
+            }
+            data += written;
+            size -= static_cast<size_t>(written);
+        }
+        return true;
+    }
+
+    bool ReadAllLocked(uint8_t* data, size_t size) {
+        while (size != 0) {
+            const ssize_t read = ::recv(fd_, data, size, 0);
+            if (read <= 0) {
+                return false;
+            }
+            data += read;
+            size -= static_cast<size_t>(read);
+        }
+        return true;
+    }
+
+    void CloseLocked() {
+        if (fd_ >= 0) {
+            ::close(fd_);
+            fd_ = -1;
+        }
+        connected_ = false;
+    }
+
+    int fd_ = -1;
+#endif
+
+    bool ReadReadyLocked() {
+        std::array<uint8_t, 8> header{};
+        if (!ReadAllLocked(header.data(), header.size())) {
+            return false;
+        }
+        uint32_t opcode = 0;
+        uint32_t size = 0;
+        for (size_t i = 0; i < 4; ++i) {
+            opcode |= static_cast<uint32_t>(header[i]) << (i * 8);
+            size |= static_cast<uint32_t>(header[4 + i]) << (i * 8);
+        }
+        if (opcode != kFrameOpcode || size > 1024 * 1024) {
+            return false;
+        }
+        std::vector<uint8_t> payload(size);
+        if (!ReadAllLocked(payload.data(), payload.size())) {
+            return false;
+        }
+        const std::string_view json(reinterpret_cast<const char*>(payload.data()), payload.size());
+        return json.find("\"evt\":\"READY\"") != std::string_view::npos;
+    }
+
+    std::mutex mutex_;
+    bool connected_ = false;
+    bool customClient_ = false;
+    std::string basicClientId_;
+    std::string clientId_;
+    Activity basicActivity_;
+    Activity activity_;
+};
+
+Client g_client;
+
+} // namespace
+
+void Initialize(const std::string& basicClientId, const std::string& basicTitle) {
+    g_client.Initialize(basicClientId, basicTitle);
+}
+
+void SetClient(const std::string& clientId) {
+    g_client.SetClient(clientId);
+}
+
+void SetActivity(Activity activity) {
+    g_client.SetActivity(std::move(activity));
+}
+
+void Reset() {
+    g_client.Reset();
+}
+
+void Shutdown() {
+    g_client.Shutdown();
+}
+
+} // namespace DiscordPresence
diff --git a/runtime/src/hle/storage/nand_isfs.cpp b/runtime/src/hle/storage/nand_isfs.cpp
index d8a0887..6ea0ad4 100644
--- a/runtime/src/hle/storage/nand_isfs.cpp
+++ b/runtime/src/hle/storage/nand_isfs.cpp
@@ -4,6 +4,7 @@
 
 #include "nand_internal.h"
 
+#include "discord_presence.h"
 #include "runtime_log.h"
 
 extern "C" void OSSleepThread_HLE_801aa9b8(CpuContext* ctx);
@@ -201,9 +202,69 @@ static int32_t HandleDolphinIoctlv(uint32_t cmd, uint32_t numIn, uint32_t numOut
         }
 
         case DOLPHIN_IOCTL_SET_SPEED_LIMIT:
-        case DOLPHIN_IOCTL_DISCORD_SET_CLIENT:
-        case DOLPHIN_IOCTL_DISCORD_SET_PRESENCE:
+            return ISFS_OK;
+
+        case DOLPHIN_IOCTL_DISCORD_SET_CLIENT: {
+            if (numIn != 1 || numOut != 0 || vectorPtr == 0) {
+                return ISFS_EINVAL;
+            }
+            const IosVector client = ReadIosVector(vectorPtr, 0);
+            if (!IsValidGuestRange(client.address, client.size)) {
+                return ISFS_EINVAL;
+            }
+            if (RuntimeConfigFile::DiscordPresenceEnabled()) {
+                DiscordPresence::SetClient(ReadGuestCString(client.address, client.size));
+            }
+            return ISFS_OK;
+        }
+
+        case DOLPHIN_IOCTL_DISCORD_SET_PRESENCE: {
+            if (numIn != 10 || numOut != 0 || vectorPtr == 0) {
+                return ISFS_EINVAL;
+            }
+            std::array<IosVector, 10> values{};
+            for (uint32_t index = 0; index < values.size(); ++index) {
+                values[index] = ReadIosVector(vectorPtr, index);
+                if (!IsValidGuestRange(values[index].address, values[index].size)) {
+                    return ISFS_EINVAL;
+                }
+            }
+            if (RuntimeConfigFile::DiscordPresenceEnabled()) {
+                DiscordPresence::Activity activity;
+                activity.details = ReadGuestCString(values[0].address, values[0].size);
+                activity.state = ReadGuestCString(values[1].address, values[1].size);
+                activity.largeImageKey = ReadGuestCString(values[2].address, values[2].size);
+                activity.largeImageText = ReadGuestCString(values[3].address, values[3].size);
+                activity.smallImageKey = ReadGuestCString(values[4].address, values[4].size);
+                activity.smallImageText = ReadGuestCString(values[5].address, values[5].size);
+                if (values[6].size >= 8 && Memory::Contains(values[6].address, 8)) {
+                    activity.startTimestamp = static_cast<int64_t>(
+                        (static_cast<uint64_t>(Memory::Read32(values[6].address)) << 32) |
+                        Memory::Read32(values[6].address + 4));
+                }
+                if (values[7].size >= 8 && Memory::Contains(values[7].address, 8)) {
+                    activity.endTimestamp = static_cast<int64_t>(
+                        (static_cast<uint64_t>(Memory::Read32(values[7].address)) << 32) |
+                        Memory::Read32(values[7].address + 4));
+                }
+                if (values[8].size >= 4) {
+                    activity.partySize = Memory::Read32(values[8].address);
+                }
+                if (values[9].size >= 4) {
+                    activity.partyMax = Memory::Read32(values[9].address);
+                }
+                DiscordPresence::SetActivity(std::move(activity));
+            }
+            return ISFS_OK;
+        }
+
         case DOLPHIN_IOCTL_DISCORD_RESET:
+            if (numIn != 0 || numOut != 0) {
+                return ISFS_EINVAL;
+            }
+            if (RuntimeConfigFile::DiscordPresenceEnabled()) {
+                DiscordPresence::Reset();
+            }
             return ISFS_OK;
 
         case DOLPHIN_IOCTL_GET_SYSTEM_TIME: {
diff --git a/runtime/src/main.cpp b/runtime/src/main.cpp
index 316220e..841cdd2 100644
--- a/runtime/src/main.cpp
+++ b/runtime/src/main.cpp
@@ -49,6 +49,7 @@
 #include "system_bridge.h"
 #include "ppc_runtime.h"
 #include "aurora_events.h"
+#include "discord_presence.h"
 #include "fiber_manager.h"
 #include "hle_stubs.h"
 #include "runtime_config.h"
@@ -1292,6 +1293,9 @@ int RuntimeMain(int argc, char** argv) {
             throw std::invalid_argument("The game runtime does not accept command-line options; use Config.toml through the installed host.");
         }
         RuntimeConfigFile::LogLoadedConfig();
+        if (RuntimeConfigFile::DiscordPresenceEnabled()) {
+            DiscordPresence::Initialize(RuntimeConfigFile::DiscordClientId(), "Mario Kart Wii");
+        }
         SystemBridge::Initialize();
         TranslatedFunctionRegistry::Finalize();
 
@@ -1418,6 +1422,7 @@ int RuntimeMain(int argc, char** argv) {
         Fiber::GuestFiberManager::Shutdown();
         WindowPlacementPersistence::Flush(true);
         aurora_shutdown();
+        DiscordPresence::Shutdown();
         SetRuntimeExitCodeImpl(0);
         ShutdownProcessTranscript();
         return 0;
@@ -1435,6 +1440,7 @@ int RuntimeMain(int argc, char** argv) {
         Fiber::GuestFiberManager::Shutdown();
         WindowPlacementPersistence::Flush(true);
         aurora_shutdown();
+        DiscordPresence::Shutdown();
         ShutdownProcessTranscript();
         return 1;
     } catch (const std::exception& ex) {
@@ -1446,6 +1452,7 @@ int RuntimeMain(int argc, char** argv) {
         Fiber::GuestFiberManager::Shutdown();
         WindowPlacementPersistence::Flush(true);
         aurora_shutdown();
+        DiscordPresence::Shutdown();
         ShutdownProcessTranscript();
         return 1;
     }