diff --git a/Sources/ContainerCommands/Container/ContainerStart.swift b/Sources/ContainerCommands/Container/ContainerStart.swift
index 349bda80..6d1f17e1 100644
--- a/Sources/ContainerCommands/Container/ContainerStart.swift
+++ b/Sources/ContainerCommands/Container/ContainerStart.swift
@@ -52,9 +52,24 @@ extension Application {
             }
             progress.start()
 
+            let detach = !self.attach && !self.interactive
             let container = try await ClientContainer.get(id: containerId)
+
+            // Bootstrap and process start are both idempotent and don't fail the second time
+            // around, however not doing an rpc is always faster :). The other bit is we don't
+            // support attach currently, so we can't do `start -a` a second time and have it succeed.
+            if container.status == .running {
+                if !detach {
+                    throw ContainerizationError(
+                        .invalidArgument,
+                        message: "attach is currently unsupported on already running containers"
+                    )
+                }
+                print(containerId)
+                return
+            }
+
             do {
-                let detach = !self.attach && !self.interactive
                 let io = try ProcessIO.create(
                     tty: container.configuration.initProcess.terminal,
                     interactive: self.interactive,
diff --git a/Sources/Services/ContainerAPIService/Containers/ContainersService.swift b/Sources/Services/ContainerAPIService/Containers/ContainersService.swift
index 1a91e31b..10af3908 100644
--- a/Sources/Services/ContainerAPIService/Containers/ContainersService.swift
+++ b/Sources/Services/ContainerAPIService/Containers/ContainersService.swift
@@ -215,6 +215,14 @@ public actor ContainersService {
         do {
             try await self.lock.withLock { context in
                 var state = try await self.getContainerState(id: id, context: context)
+
+                // We've already bootstrapped this container. Ideally we should be able to
+                // return some sort of error code from the sandbox svc to check here, but this
+                // is also a very simple check and faster than doing an rpc to get the same result.
+                if state.client != nil {
+                    return
+                }
+
                 let runtime = state.snapshot.configuration.runtimeHandler
                 let sandboxClient = try await SandboxClient.create(
                     id: id,
diff --git a/Tests/CLITests/Subcommands/Run/TestCLIRunLifecycle.swift b/Tests/CLITests/Subcommands/Run/TestCLIRunLifecycle.swift
index 9a095029..bef9fb83 100644
--- a/Tests/CLITests/Subcommands/Run/TestCLIRunLifecycle.swift
+++ b/Tests/CLITests/Subcommands/Run/TestCLIRunLifecycle.swift
@@ -44,4 +44,43 @@ class TestCLIRunLifecycle: CLITest {
             try self.doStop(name: name)
         }
     }
+
+    @Test func testStartIdempotent() throws {
+        let name = getTestName()
+
+        #expect(throws: Never.self, "expected container run to succeed") {
+            try self.doLongRun(name: name, args: [])
+            defer {
+                try? self.doStop(name: name)
+            }
+            try self.waitForContainerRunning(name)
+
+            let (output, _, status) = try self.run(arguments: ["start", name])
+            #expect(status == 0, "expected start to succeed on already running container")
+            #expect(output.trimmingCharacters(in: .whitespacesAndNewlines) == name, "expected output to be container name")
+
+            // Don't care about the resp, just that the container is still there and not cleaned up.
+            let _ = try inspectContainer(name)
+
+            try self.doStop(name: name)
+        }
+    }
+
+    @Test func testStartIdempotentAttachFails() throws {
+        let name = getTestName()
+
+        #expect(throws: Never.self, "expected container run to succeed") {
+            try self.doLongRun(name: name, args: [])
+            defer {
+                try? self.doStop(name: name)
+            }
+            try self.waitForContainerRunning(name)
+
+            let (_, error, status) = try self.run(arguments: ["start", "-a", name])
+            #expect(status != 0, "expected start with attach to fail on already running container")
+            #expect(error.contains("attach is currently unsupported on already running containers"), "expected error message about attach not supported")
+
+            try self.doStop(name: name)
+        }
+    }
 }