diff --git a/crates/uv-client/src/registry_client.rs b/crates/uv-client/src/registry_client.rs
index 7f6ff4696..40127e044 100644
--- a/crates/uv-client/src/registry_client.rs
+++ b/crates/uv-client/src/registry_client.rs
@@ -850,9 +850,10 @@ impl MediaType {
     }
 }
 
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Default)]
 pub enum Connectivity {
     /// Allow access to the network.
+    #[default]
     Online,
 
     /// Do not allow access to the network.
diff --git a/crates/uv/src/cli.rs b/crates/uv/src/cli.rs
index 2f47172fe..8f1d3fa0b 100644
--- a/crates/uv/src/cli.rs
+++ b/crates/uv/src/cli.rs
@@ -1840,6 +1840,13 @@ pub(crate) struct RunArgs {
     #[arg(long)]
     pub(crate) with: Vec<String>,
 
+    /// Run offline, i.e., without accessing the network.
+    #[arg(global = true, long, overrides_with("no_offline"))]
+    pub(crate) offline: bool,
+
+    #[arg(long, overrides_with("offline"), hide = true)]
+    pub(crate) no_offline: bool,
+
     /// The Python interpreter to use to build the run environment.
     ///
     /// By default, `uv` uses the virtual environment in the current working directory or any parent
@@ -1954,4 +1961,11 @@ pub(crate) struct ToolRunArgs {
         group = "discovery"
     )]
     pub(crate) python: Option<String>,
+
+    /// Run offline, i.e., without accessing the network.
+    #[arg(global = true, long, overrides_with("no_offline"))]
+    pub(crate) offline: bool,
+
+    #[arg(long, overrides_with("offline"), hide = true)]
+    pub(crate) no_offline: bool,
 }
diff --git a/crates/uv/src/commands/project/mod.rs b/crates/uv/src/commands/project/mod.rs
index de6c1f326..8817a946e 100644
--- a/crates/uv/src/commands/project/mod.rs
+++ b/crates/uv/src/commands/project/mod.rs
@@ -11,7 +11,7 @@ use platform_tags::Tags;
 use pypi_types::Yanked;
 use tracing::debug;
 use uv_cache::Cache;
-use uv_client::{BaseClientBuilder, RegistryClient, RegistryClientBuilder};
+use uv_client::{BaseClientBuilder, Connectivity, RegistryClient, RegistryClientBuilder};
 use uv_configuration::{
     Concurrency, ConfigSettings, Constraints, NoBinary, NoBuild, Overrides, PreviewMode, Reinstall,
     SetupPyStrategy,
@@ -468,11 +468,12 @@ pub(crate) async fn update_environment(
     venv: PythonEnvironment,
     requirements: &[RequirementsSource],
     preview: PreviewMode,
+    connectivity: Connectivity,
     cache: &Cache,
     printer: Printer,
 ) -> Result<PythonEnvironment> {
     // TODO(zanieb): Support client configuration
-    let client_builder = BaseClientBuilder::default();
+    let client_builder = BaseClientBuilder::default().connectivity(connectivity);
 
     // Read all requirements from the provided sources.
     // TODO(zanieb): Consider allowing constraints and extras
@@ -524,6 +525,7 @@ pub(crate) async fn update_environment(
     // Initialize the registry client.
     // TODO(zanieb): Support client options e.g. offline, tls, etc.
     let client = RegistryClientBuilder::new(cache.clone())
+        .connectivity(connectivity)
         .markers(markers)
         .platform(venv.interpreter().platform())
         .build();
diff --git a/crates/uv/src/commands/project/run.rs b/crates/uv/src/commands/project/run.rs
index b23c70808..5aa9904d8 100644
--- a/crates/uv/src/commands/project/run.rs
+++ b/crates/uv/src/commands/project/run.rs
@@ -8,6 +8,7 @@ use tokio::process::Command;
 use tracing::debug;
 
 use uv_cache::Cache;
+use uv_client::Connectivity;
 use uv_configuration::PreviewMode;
 use uv_interpreter::{PythonEnvironment, SystemPython};
 use uv_requirements::{ProjectWorkspace, RequirementsSource};
@@ -25,6 +26,7 @@ pub(crate) async fn run(
     python: Option<String>,
     isolated: bool,
     preview: PreviewMode,
+    connectivity: Connectivity,
     cache: &Cache,
     printer: Printer,
 ) -> Result<ExitStatus> {
@@ -60,8 +62,15 @@ pub(crate) async fn run(
 
         // Install the project requirements.
         Some(
-            project::update_environment(venv, &project.requirements(), preview, cache, printer)
-                .await?,
+            project::update_environment(
+                venv,
+                &project.requirements(),
+                preview,
+                connectivity,
+                cache,
+                printer,
+            )
+            .await?,
         )
     };
 
@@ -101,7 +110,10 @@ pub(crate) async fn run(
         )?;
 
         // Install the ephemeral requirements.
-        Some(project::update_environment(venv, &requirements, preview, cache, printer).await?)
+        Some(
+            project::update_environment(venv, &requirements, preview, connectivity, cache, printer)
+                .await?,
+        )
     };
 
     // Construct the command
diff --git a/crates/uv/src/commands/tool/run.rs b/crates/uv/src/commands/tool/run.rs
index 7b82f6d2c..7e7b63e47 100644
--- a/crates/uv/src/commands/tool/run.rs
+++ b/crates/uv/src/commands/tool/run.rs
@@ -8,6 +8,7 @@ use tokio::process::Command;
 use tracing::debug;
 
 use uv_cache::Cache;
+use uv_client::Connectivity;
 use uv_configuration::PreviewMode;
 use uv_interpreter::{PythonEnvironment, SystemPython};
 use uv_requirements::RequirementsSource;
@@ -25,6 +26,7 @@ pub(crate) async fn run(
     python: Option<String>,
     _isolated: bool,
     preview: PreviewMode,
+    connectivity: Connectivity,
     cache: &Cache,
     printer: Printer,
 ) -> Result<ExitStatus> {
@@ -65,7 +67,7 @@ pub(crate) async fn run(
 
     // Install the ephemeral requirements.
     let ephemeral_env =
-        Some(update_environment(venv, &requirements, preview, cache, printer).await?);
+        Some(update_environment(venv, &requirements, preview, connectivity, cache, printer).await?);
 
     // TODO(zanieb): Determine the command via the package entry points
     let command = target;
diff --git a/crates/uv/src/main.rs b/crates/uv/src/main.rs
index 24b31701a..149bf7820 100644
--- a/crates/uv/src/main.rs
+++ b/crates/uv/src/main.rs
@@ -12,6 +12,7 @@ use owo_colors::OwoColorize;
 use tracing::instrument;
 
 use uv_cache::Cache;
+use uv_client::Connectivity;
 use uv_requirements::RequirementsSource;
 use uv_workspace::Combine;
 
@@ -565,6 +566,7 @@ async fn run() -> Result<ExitStatus> {
                 args.python,
                 globals.isolated,
                 globals.preview,
+                args.connectivity,
                 &cache,
                 printer,
             )
@@ -603,12 +605,18 @@ async fn run() -> Result<ExitStatus> {
         Commands::Tool(ToolNamespace {
             command: ToolCommand::Run(args),
         }) => {
+            let connectivity = if args.offline {
+                Connectivity::Offline
+            } else {
+                Connectivity::Online
+            };
             commands::run_tool(
                 args.target,
                 args.args,
                 args.python,
                 globals.isolated,
                 globals.preview,
+                connectivity,
                 &cache,
                 printer,
             )
diff --git a/crates/uv/src/settings.rs b/crates/uv/src/settings.rs
index cf046df27..ea377ff3d 100644
--- a/crates/uv/src/settings.rs
+++ b/crates/uv/src/settings.rs
@@ -94,6 +94,10 @@ pub(crate) struct RunSettings {
     pub(crate) args: Vec<OsString>,
     pub(crate) with: Vec<String>,
     pub(crate) python: Option<String>,
+
+    // Shared settings.
+    // TODO(zanieb): should be moved to a global setting
+    pub(crate) connectivity: Connectivity,
 }
 
 impl RunSettings {
@@ -105,6 +109,8 @@ impl RunSettings {
             args,
             with,
             python,
+            offline,
+            no_offline,
         } = args;
 
         Self {
@@ -113,6 +119,16 @@ impl RunSettings {
             args,
             with,
             python,
+            // Shared settings
+            connectivity: flag(offline, no_offline)
+                .map(|offline| {
+                    if offline {
+                        Connectivity::Offline
+                    } else {
+                        Connectivity::Online
+                    }
+                })
+                .unwrap_or_default(),
         }
     }
 }