diff --git a/crates/uv-resolver/src/lock/mod.rs b/crates/uv-resolver/src/lock/mod.rs
index 49cb851b3..2e3ee56d4 100644
--- a/crates/uv-resolver/src/lock/mod.rs
+++ b/crates/uv-resolver/src/lock/mod.rs
@@ -1431,7 +1431,7 @@ impl Lock {
         }
 
         // Collect the set of available indexes (both `--index-url` and `--find-links` entries).
-        let remotes = indexes.map(|locations| {
+        let mut remotes = indexes.map(|locations| {
             locations
                 .allowed_indexes()
                 .into_iter()
@@ -1444,7 +1444,7 @@ impl Lock {
                 .collect::<BTreeSet<_>>()
         });
 
-        let locals = indexes.map(|locations| {
+        let mut locals = indexes.map(|locations| {
             locations
                 .allowed_indexes()
                 .into_iter()
@@ -1717,6 +1717,38 @@ impl Lock {
                 return Ok(SatisfiesResult::MissingVersion(&package.id.name));
             }
 
+            // Add any explicit indexes to the list of known locals or remotes. These indexes may
+            // not be available as top-level configuration (i.e., if they're defined within a
+            // workspace member), but we already validated that the dependencies are up-to-date, so
+            // we can consider them "available".
+            for requirement in &package.metadata.requires_dist {
+                if let RequirementSource::Registry {
+                    index: Some(index), ..
+                } = &requirement.source
+                {
+                    match &index.url {
+                        IndexUrl::Pypi(_) | IndexUrl::Url(_) => {
+                            if let Some(remotes) = remotes.as_mut() {
+                                remotes.insert(UrlString::from(
+                                    index.url().without_credentials().as_ref(),
+                                ));
+                            }
+                        }
+                        IndexUrl::Path(url) => {
+                            if let Some(locals) = locals.as_mut() {
+                                if let Some(path) = url.to_file_path().ok().and_then(|path| {
+                                    relative_to(&path, root)
+                                        .or_else(|_| std::path::absolute(path))
+                                        .ok()
+                                }) {
+                                    locals.insert(path.into_boxed_path());
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+
             // Recurse.
             for dep in &package.dependencies {
                 if seen.insert(&dep.package_id) {
diff --git a/crates/uv/tests/it/lock.rs b/crates/uv/tests/it/lock.rs
index 8a006ffb6..9f38a168a 100644
--- a/crates/uv/tests/it/lock.rs
+++ b/crates/uv/tests/it/lock.rs
@@ -29411,3 +29411,490 @@ fn test_tilde_equals_python_version() -> Result<()> {
 
     Ok(())
 }
+
+/// Test that lockfile validation includes explicit indexes from path dependencies.
+/// <https://github.com/astral-sh/uv/issues/11419>
+#[test]
+fn lock_path_dependency_explicit_index() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    // Create the path dependency with explicit index
+    let pkg_a = context.temp_dir.child("pkg_a");
+    fs_err::create_dir_all(&pkg_a)?;
+
+    let pyproject_toml = pkg_a.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-a"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["iniconfig"]
+
+        [tool.uv.sources]
+        iniconfig = { index = "inner-index" }
+
+        [[tool.uv.index]]
+        name = "inner-index"
+        url = "https://pypi-proxy.fly.dev/simple"
+        explicit = true
+        "#,
+    )?;
+
+    // Create a project that depends on pkg_a
+    let pkg_b = context.temp_dir.child("pkg_b");
+    fs_err::create_dir_all(&pkg_b)?;
+
+    let pyproject_toml = pkg_b.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-b"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["pkg-a"]
+
+        [tool.uv.sources]
+        pkg-a = { path = "../pkg_a/", editable = true }
+        black = { index = "outer-index" }
+
+        [[tool.uv.index]]
+        name = "outer-index"
+        url = "https://outer-index.com/simple"
+        explicit = true
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock().current_dir(&pkg_b), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 3 packages in [TIME]
+    ");
+
+    uv_snapshot!(context.filters(), context.lock().arg("--check").current_dir(&pkg_b), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 3 packages in [TIME]
+    ");
+
+    Ok(())
+}
+
+/// Test that lockfile validation includes explicit indexes from path dependencies
+/// defined in a non-root workspace member.
+#[test]
+fn lock_path_dependency_explicit_index_workspace_member() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    // Create the path dependency with explicit index
+    let pkg_a = context.temp_dir.child("pkg_a");
+    fs_err::create_dir_all(&pkg_a)?;
+
+    let pyproject_toml = pkg_a.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-a"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["iniconfig"]
+
+        [tool.uv.sources]
+        iniconfig = { index = "inner-index" }
+
+        [[tool.uv.index]]
+        name = "inner-index"
+        url = "https://pypi-proxy.fly.dev/simple"
+        explicit = true
+        "#,
+    )?;
+
+    // Create a project that depends on pkg_a
+    let member = context.temp_dir.child("member");
+    fs_err::create_dir_all(&member)?;
+
+    let pyproject_toml = member.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "member"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["pkg-a"]
+
+        [tool.uv.sources]
+        pkg-a = { path = "../pkg_a/", editable = true }
+        black = { index = "middle-index" }
+
+        [[tool.uv.index]]
+        name = "middle-index"
+        url = "https://middle-index.com/simple"
+        explicit = true
+        "#,
+    )?;
+
+    // Create a root with workspace member
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "root-project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["member"]
+
+        [tool.uv.workspace]
+        members = ["member"]
+
+        [tool.uv.sources]
+        member = { workspace = true }
+        anyio = { index = "outer-index" }
+
+        [[tool.uv.index]]
+        name = "outer-index"
+        url = "https://outer-index.com/simple"
+        explicit = true
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock(), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 4 packages in [TIME]
+    ");
+
+    uv_snapshot!(context.filters(), context.lock().arg("--check"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 4 packages in [TIME]
+    ");
+
+    Ok(())
+}
+
+/// Test that lockfile validation works correctly when path dependency has
+/// both explicit and non-explicit indexes.
+#[test]
+fn lock_path_dependency_mixed_indexes() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    // Create the path dependency with both explicit and non-explicit indexes.
+    let pkg_a = context.temp_dir.child("pkg_a");
+    fs_err::create_dir_all(&pkg_a)?;
+
+    let pyproject_toml = pkg_a.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-a"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["iniconfig", "anyio"]
+
+        [tool.uv.sources]
+        iniconfig = { index = "explicit-index" }
+        anyio = { index = "non-explicit-index" }
+
+        [[tool.uv.index]]
+        name = "non-explicit-index"
+        url = "https://pypi-proxy.fly.dev/simple"
+
+        [[tool.uv.index]]
+        name = "explicit-index"
+        url = "https://pypi.org/simple"
+        explicit = true
+        "#,
+    )?;
+
+    // Create a project that depends on pkg_a.
+    let pkg_b = context.temp_dir.child("pkg_b");
+    fs_err::create_dir_all(&pkg_b)?;
+
+    let pyproject_toml = pkg_b.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-b"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["pkg-a"]
+
+        [tool.uv.sources]
+        pkg-a = { path = "../pkg_a/", editable = true }
+        black = { index = "outer-index" }
+
+        [[tool.uv.index]]
+        name = "outer-index"
+        url = "https://outer-index.com/simple"
+        explicit = true
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock().current_dir(&pkg_b), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 6 packages in [TIME]
+    ");
+
+    uv_snapshot!(context.filters(), context.lock().arg("--check").current_dir(&pkg_b), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 6 packages in [TIME]
+    ");
+
+    Ok(())
+}
+
+/// Test that path dependencies without an index don't affect validation.
+#[test]
+fn lock_path_dependency_no_index() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    // Create the path dependency without explicit indexes.
+    let pkg_a = context.temp_dir.child("pkg_a");
+    fs_err::create_dir_all(&pkg_a)?;
+
+    let pyproject_toml = pkg_a.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-a"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["requests"]
+        "#,
+    )?;
+
+    // Create a project that depends on pkg_a.
+    let pkg_b = context.temp_dir.child("pkg_b");
+    fs_err::create_dir_all(&pkg_b)?;
+
+    let pyproject_toml = pkg_b.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-b"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["pkg-a"]
+
+        [tool.uv.sources]
+        pkg-a = { path = "../pkg_a/", editable = true }
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock().current_dir(&pkg_b), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 7 packages in [TIME]
+    ");
+
+    uv_snapshot!(context.filters(), context.lock().arg("--check").current_dir(&pkg_b), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 7 packages in [TIME]
+    ");
+
+    Ok(())
+}
+
+/// Test that a nested path dependency with an explicit index validates correctly.
+#[test]
+fn lock_nested_path_dependency_explicit_index() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    // Create the inner dependency with explicit index.
+    let pkg_a = context.temp_dir.child("pkg_a");
+    fs_err::create_dir_all(&pkg_a)?;
+
+    let pyproject_toml = pkg_a.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-a"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["iniconfig"]
+
+        [tool.uv.sources]
+        iniconfig = { index = "inner-index" }
+
+        [[tool.uv.index]]
+        name = "inner-index"
+        url = "https://pypi-proxy.fly.dev/simple"
+        explicit = true
+        "#,
+    )?;
+
+    // Create intermediate dependency that depends on pkg_a.
+    let pkg_b = context.temp_dir.child("pkg_b");
+    fs_err::create_dir_all(&pkg_b)?;
+
+    let pyproject_toml = pkg_b.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-b"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["pkg-a"]
+
+        [tool.uv.sources]
+        pkg-a = { path = "../pkg_a/", editable = true }
+        "#,
+    )?;
+
+    // Create a project that depends on intermediate dependency.
+    let pkg_c = context.temp_dir.child("pkg_c");
+    fs_err::create_dir_all(&pkg_c)?;
+
+    let pyproject_toml = pkg_c.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-c"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["pkg-b"]
+
+        [tool.uv.sources]
+        pkg-b = { path = "../pkg_b/", editable = true }
+        black = { index = "outer-index" }
+
+        [[tool.uv.index]]
+        name = "outer-index"
+        url = "https://outer-index.com/simple"
+        explicit = true
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock().current_dir(&pkg_c), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 4 packages in [TIME]
+    ");
+
+    uv_snapshot!(context.filters(), context.lock().arg("--check").current_dir(&pkg_c), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 4 packages in [TIME]
+    ");
+
+    Ok(())
+}
+
+/// Test that validating circular path dependency indexes doesn't cause an infinite loop.
+#[test]
+fn lock_circular_path_dependency_explicit_index() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    // Create pkg_a (with explicit index) that depends on pkg_b.
+    let pkg_a = context.temp_dir.child("pkg_a");
+    fs_err::create_dir_all(&pkg_a)?;
+
+    let pyproject_toml = pkg_a.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-a"
+        version = "0.1.0"
+        requires-python = ">=3.10"
+        dependencies = ["pkg-b", "iniconfig"]
+
+        [tool.uv.sources]
+        pkg-b = { path = "../pkg_b/" }
+        iniconfig = { index = "index-a" }
+
+        [[tool.uv.index]]
+        name = "index-a"
+        url = "https://pypi-proxy.fly.dev/simple"
+        explicit = true
+        "#,
+    )?;
+
+    // Create pkg_b that depends on pkg_a. This is a circular dependency.
+    let pkg_b = context.temp_dir.child("pkg_b");
+    fs_err::create_dir_all(&pkg_b)?;
+
+    let pyproject_toml = pkg_b.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pkg-b"
+        version = "0.1.0"
+        requires-python = ">=3.10"
+        dependencies = ["pkg-a", "anyio"]
+
+        [tool.uv.sources]
+        pkg-a = { path = "../pkg_a/" }
+        anyio = { index = "index-b" }
+
+        [[tool.uv.index]]
+        name = "index-b"
+        url = "https://pypi.org/simple"
+        explicit = true
+        default = true
+        "#,
+    )?;
+
+    // This should not hang or crash due to the circular dependency.
+    uv_snapshot!(context.filters(), context.lock().current_dir(&pkg_a), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 8 packages in [TIME]
+    ");
+
+    uv_snapshot!(context.filters(), context.lock().arg("--check").current_dir(&pkg_a), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Resolved 8 packages in [TIME]
+    ");
+
+    Ok(())
+}