diff --git a/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx b/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
index b9b2e2a62..62bf0fa79 100644
--- a/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
+++ b/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
@@ -93,6 +93,7 @@ import { DialogGoUpsell } from "../../component/dialog-go-upsell"
 import { DialogTokenPlan } from "../../component/dialog-token-plan"
 import { SessionRetry } from "@/session/retry"
 import { getRevertDiffFiles } from "../../util/revert-diff"
+import { conversationScrollKey } from "./scroll"
 
 addDefaultParsers(parsers.parsers)
 
@@ -1082,8 +1083,9 @@ export function Session() {
     }
   })
 
-  // snap to bottom when session changes
-  createEffect(on(() => route.sessionID, toBottom))
+  // Snap to bottom when the rendered conversation changes. Subagent views share
+  // the same sessionID, so key by agentID as well as sessionID.
+  createEffect(on(() => conversationScrollKey({ sessionID: route.sessionID, agentID: currentAgentID() }), toBottom))
 
   return (
     <context.Provider
diff --git a/packages/opencode/src/cli/cmd/tui/routes/session/scroll.ts b/packages/opencode/src/cli/cmd/tui/routes/session/scroll.ts
new file mode 100644
index 000000000..590a27e6e
--- /dev/null
+++ b/packages/opencode/src/cli/cmd/tui/routes/session/scroll.ts
@@ -0,0 +1,3 @@
+export function conversationScrollKey(input: { sessionID: string; agentID?: string }) {
+  return `${input.sessionID}:${input.agentID ?? "main"}`
+}
diff --git a/packages/opencode/test/cli/tui/session-scroll.test.ts b/packages/opencode/test/cli/tui/session-scroll.test.ts
new file mode 100644
index 000000000..a495db29b
--- /dev/null
+++ b/packages/opencode/test/cli/tui/session-scroll.test.ts
@@ -0,0 +1,11 @@
+import { expect, test } from "bun:test"
+import { conversationScrollKey } from "../../../src/cli/cmd/tui/routes/session/scroll"
+
+test("conversationScrollKey changes when switching between main and subagent views", () => {
+  expect(conversationScrollKey({ sessionID: "ses_1", agentID: "main" })).toBe("ses_1:main")
+  expect(conversationScrollKey({ sessionID: "ses_1", agentID: "agent_1" })).toBe("ses_1:agent_1")
+})
+
+test("conversationScrollKey defaults missing agentID to main", () => {
+  expect(conversationScrollKey({ sessionID: "ses_1" })).toBe("ses_1:main")
+})