diff --git a/CHANGELOG.md b/CHANGELOG.md
index 50041a08d..ec855342a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Fixed `ui.tooltip()`'s `options` parameter to properly pass Bootstrap tooltip options to the underlying web component. (#2101)
 
+* Fixed an issue where `session.bookmark()` would error when non-existent `input` values are read. (#2117)
+
 * Revised `accordion()`'s `open` logic to close all panels when an empty list is passed. (#2109)
 
 ## [1.5.0] - 2025-09-11
diff --git a/shiny/session/_session.py b/shiny/session/_session.py
index f13a970b3..ed1fc876b 100644
--- a/shiny/session/_session.py
+++ b/shiny/session/_session.py
@@ -1477,7 +1477,11 @@ async def _serialize(
                     continue
                 if key in exclude_set:
                     continue
-                val = value()
+
+                try:
+                    val = value()
+                except SilentException:
+                    continue
 
                 # Possibly apply custom serialization given the input id
                 serializer = self._serializers.get(key, serializer_default)
diff --git a/tests/playwright/shiny/bookmark/modal/app.py b/tests/playwright/shiny/bookmark/modal/app.py
index 68f66c4f3..4e3a97bcc 100644
--- a/tests/playwright/shiny/bookmark/modal/app.py
+++ b/tests/playwright/shiny/bookmark/modal/app.py
@@ -9,12 +9,19 @@ def app_ui(request: Request):
     )
 
 
-def server(input: Inputs, ouput: Outputs, session: Session):
+def server(input: Inputs, output: Outputs, session: Session):
 
     @reactive.effect
     @reactive.event(input.letter, ignore_init=True)
     async def _():
         await session.bookmark()
 
+    # Just to make sure that missing inputs don't break bookmarking
+    # behavior (https://github.com/posit-dev/py-shiny/pull/2117)
+    @reactive.effect
+    @reactive.event(input.non_existent_input)
+    def _():
+        pass
+
 
 app = App(app_ui, server, bookmark_store="url")
diff --git a/tests/playwright/shiny/bookmark/modal/test_bookmark_modal.py b/tests/playwright/shiny/bookmark/modal/test_bookmark_modal.py
index e3d8fbf41..555f84fa9 100644
--- a/tests/playwright/shiny/bookmark/modal/test_bookmark_modal.py
+++ b/tests/playwright/shiny/bookmark/modal/test_bookmark_modal.py
@@ -19,3 +19,4 @@ def test_bookmark_modules(page: Page, local_app: ShinyAppProc):
     )
 
     assert "?" not in page.url
+    assert "An error has occurred" not in page.inner_text("body")