diff --git a/changelog/fixed/stopwatch-sloth.md b/changelog/fixed/stopwatch-sloth.md
new file mode 100644
index 00000000..41152d42
--- /dev/null
+++ b/changelog/fixed/stopwatch-sloth.md
@@ -0,0 +1 @@
+Time search attribute values now keep sub-second precision, and setting one no longer raises `NoMethodError` when the application has not required `time`.
diff --git a/temporalio/lib/temporalio/search_attributes.rb b/temporalio/lib/temporalio/search_attributes.rb
index 32b05bad..ac5c6ae7 100644
--- a/temporalio/lib/temporalio/search_attributes.rb
+++ b/temporalio/lib/temporalio/search_attributes.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'temporalio/api'
+require 'time'
 
 module Temporalio
   # Collection of typed search attributes.
@@ -142,8 +143,9 @@ def self._value_from_payload(payload)
 
     # @!visibility private
     def self._to_proto_pair(key, value)
-      # We use a default converter, but if type is a time, we need ISO format
-      value = value.iso8601 if key.type == IndexedValueType::TIME && value.is_a?(Time)
+      # We use a default converter, but if type is a time, we need ISO format with nanoseconds since the server keeps
+      # sub-second precision
+      value = value.iso8601(9) if key.type == IndexedValueType::TIME && value.is_a?(Time)
 
       # Convert to payload
       payload = Converters::PayloadConverter.default.to_payload(value)
diff --git a/temporalio/test/client_workflow_test.rb b/temporalio/test/client_workflow_test.rb
index e481ae82..2cec8c57 100644
--- a/temporalio/test/client_workflow_test.rb
+++ b/temporalio/test/client_workflow_test.rb
@@ -122,6 +122,23 @@ def test_lazy_connect
     assert client.connection.connected?
   end
 
+  exclude_from_cloud :needs_cloud_adaptation,
+                     'Requires custom search attributes that the Cloud harness does not provision.'
+  def test_search_attribute_time_sub_second
+    env.ensure_common_search_attribute_keys
+
+    time = Time.at(1_800_000_000, 123_456_789, :nanosecond, in: 'UTC')
+    handle = env.client.start_workflow(
+      'does-not-exist',
+      id: "wf-#{SecureRandom.uuid}",
+      task_queue: "tq-#{SecureRandom.uuid}",
+      search_attributes: Temporalio::SearchAttributes.new({ ATTR_KEY_TIME => time })
+    )
+    assert_equal time, handle.describe.search_attributes&.[](ATTR_KEY_TIME)
+  ensure
+    handle&.terminate
+  end
+
   exclude_from_cloud :needs_cloud_adaptation,
                      'Requires custom search attributes and a Go worker with Cloud TLS configuration.'
   def test_describe