diff --git a/bazel/experiments.bzl b/bazel/experiments.bzl
index 5ae6526b4ad..1fc7f607ea8 100644
--- a/bazel/experiments.bzl
+++ b/bazel/experiments.bzl
@@ -34,6 +34,7 @@ EXPERIMENT_ENABLES = {
     "server_privacy": "server_privacy",
     "tcp_frame_size_tuning": "tcp_frame_size_tuning",
     "tcp_rcv_lowat": "tcp_rcv_lowat",
+    "time_caching_in_party": "time_caching_in_party",
     "trace_record_callops": "trace_record_callops",
     "unconstrained_max_quota_buffer_size": "unconstrained_max_quota_buffer_size",
     "work_serializer_clears_time_cache": "work_serializer_clears_time_cache",
diff --git a/src/core/lib/experiments/experiments.cc b/src/core/lib/experiments/experiments.cc
index 8a8b5a445e1..96a2c734308 100644
--- a/src/core/lib/experiments/experiments.cc
+++ b/src/core/lib/experiments/experiments.cc
@@ -79,6 +79,10 @@ const char* const additional_constraints_tcp_frame_size_tuning = "{}";
 const char* const description_tcp_rcv_lowat =
     "Use SO_RCVLOWAT to avoid wakeups on the read path.";
 const char* const additional_constraints_tcp_rcv_lowat = "{}";
+const char* const description_time_caching_in_party =
+    "Disable time caching in exec_ctx, and enable it only in a single party "
+    "execution.";
+const char* const additional_constraints_time_caching_in_party = "{}";
 const char* const description_trace_record_callops =
     "Enables tracing of call batch initiation and completion.";
 const char* const additional_constraints_trace_record_callops = "{}";
@@ -141,6 +145,8 @@ const ExperimentMetadata g_experiment_metadata[] = {
      additional_constraints_tcp_frame_size_tuning, nullptr, 0, false, true},
     {"tcp_rcv_lowat", description_tcp_rcv_lowat,
      additional_constraints_tcp_rcv_lowat, nullptr, 0, false, true},
+    {"time_caching_in_party", description_time_caching_in_party,
+     additional_constraints_time_caching_in_party, nullptr, 0, true, true},
     {"trace_record_callops", description_trace_record_callops,
      additional_constraints_trace_record_callops, nullptr, 0, true, true},
     {"unconstrained_max_quota_buffer_size",
@@ -216,6 +222,10 @@ const char* const additional_constraints_tcp_frame_size_tuning = "{}";
 const char* const description_tcp_rcv_lowat =
     "Use SO_RCVLOWAT to avoid wakeups on the read path.";
 const char* const additional_constraints_tcp_rcv_lowat = "{}";
+const char* const description_time_caching_in_party =
+    "Disable time caching in exec_ctx, and enable it only in a single party "
+    "execution.";
+const char* const additional_constraints_time_caching_in_party = "{}";
 const char* const description_trace_record_callops =
     "Enables tracing of call batch initiation and completion.";
 const char* const additional_constraints_trace_record_callops = "{}";
@@ -278,6 +288,8 @@ const ExperimentMetadata g_experiment_metadata[] = {
      additional_constraints_tcp_frame_size_tuning, nullptr, 0, false, true},
     {"tcp_rcv_lowat", description_tcp_rcv_lowat,
      additional_constraints_tcp_rcv_lowat, nullptr, 0, false, true},
+    {"time_caching_in_party", description_time_caching_in_party,
+     additional_constraints_time_caching_in_party, nullptr, 0, true, true},
     {"trace_record_callops", description_trace_record_callops,
      additional_constraints_trace_record_callops, nullptr, 0, true, true},
     {"unconstrained_max_quota_buffer_size",
@@ -353,6 +365,10 @@ const char* const additional_constraints_tcp_frame_size_tuning = "{}";
 const char* const description_tcp_rcv_lowat =
     "Use SO_RCVLOWAT to avoid wakeups on the read path.";
 const char* const additional_constraints_tcp_rcv_lowat = "{}";
+const char* const description_time_caching_in_party =
+    "Disable time caching in exec_ctx, and enable it only in a single party "
+    "execution.";
+const char* const additional_constraints_time_caching_in_party = "{}";
 const char* const description_trace_record_callops =
     "Enables tracing of call batch initiation and completion.";
 const char* const additional_constraints_trace_record_callops = "{}";
@@ -415,6 +431,8 @@ const ExperimentMetadata g_experiment_metadata[] = {
      additional_constraints_tcp_frame_size_tuning, nullptr, 0, false, true},
     {"tcp_rcv_lowat", description_tcp_rcv_lowat,
      additional_constraints_tcp_rcv_lowat, nullptr, 0, false, true},
+    {"time_caching_in_party", description_time_caching_in_party,
+     additional_constraints_time_caching_in_party, nullptr, 0, true, true},
     {"trace_record_callops", description_trace_record_callops,
      additional_constraints_trace_record_callops, nullptr, 0, true, true},
     {"unconstrained_max_quota_buffer_size",
diff --git a/src/core/lib/experiments/experiments.h b/src/core/lib/experiments/experiments.h
index 0b44aca703f..b6fb4257c58 100644
--- a/src/core/lib/experiments/experiments.h
+++ b/src/core/lib/experiments/experiments.h
@@ -78,6 +78,8 @@ inline bool IsScheduleCancellationOverWriteEnabled() { return false; }
 inline bool IsServerPrivacyEnabled() { return false; }
 inline bool IsTcpFrameSizeTuningEnabled() { return false; }
 inline bool IsTcpRcvLowatEnabled() { return false; }
+#define GRPC_EXPERIMENT_IS_INCLUDED_TIME_CACHING_IN_PARTY
+inline bool IsTimeCachingInPartyEnabled() { return true; }
 #define GRPC_EXPERIMENT_IS_INCLUDED_TRACE_RECORD_CALLOPS
 inline bool IsTraceRecordCallopsEnabled() { return true; }
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() { return false; }
@@ -110,6 +112,8 @@ inline bool IsScheduleCancellationOverWriteEnabled() { return false; }
 inline bool IsServerPrivacyEnabled() { return false; }
 inline bool IsTcpFrameSizeTuningEnabled() { return false; }
 inline bool IsTcpRcvLowatEnabled() { return false; }
+#define GRPC_EXPERIMENT_IS_INCLUDED_TIME_CACHING_IN_PARTY
+inline bool IsTimeCachingInPartyEnabled() { return true; }
 #define GRPC_EXPERIMENT_IS_INCLUDED_TRACE_RECORD_CALLOPS
 inline bool IsTraceRecordCallopsEnabled() { return true; }
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() { return false; }
@@ -141,6 +145,8 @@ inline bool IsScheduleCancellationOverWriteEnabled() { return false; }
 inline bool IsServerPrivacyEnabled() { return false; }
 inline bool IsTcpFrameSizeTuningEnabled() { return false; }
 inline bool IsTcpRcvLowatEnabled() { return false; }
+#define GRPC_EXPERIMENT_IS_INCLUDED_TIME_CACHING_IN_PARTY
+inline bool IsTimeCachingInPartyEnabled() { return true; }
 #define GRPC_EXPERIMENT_IS_INCLUDED_TRACE_RECORD_CALLOPS
 inline bool IsTraceRecordCallopsEnabled() { return true; }
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() { return false; }
@@ -168,6 +174,7 @@ enum ExperimentIds {
   kExperimentIdServerPrivacy,
   kExperimentIdTcpFrameSizeTuning,
   kExperimentIdTcpRcvLowat,
+  kExperimentIdTimeCachingInParty,
   kExperimentIdTraceRecordCallops,
   kExperimentIdUnconstrainedMaxQuotaBufferSize,
   kExperimentIdWorkSerializerClearsTimeCache,
@@ -242,6 +249,10 @@ inline bool IsTcpFrameSizeTuningEnabled() {
 inline bool IsTcpRcvLowatEnabled() {
   return IsExperimentEnabled<kExperimentIdTcpRcvLowat>();
 }
+#define GRPC_EXPERIMENT_IS_INCLUDED_TIME_CACHING_IN_PARTY
+inline bool IsTimeCachingInPartyEnabled() {
+  return IsExperimentEnabled<kExperimentIdTimeCachingInParty>();
+}
 #define GRPC_EXPERIMENT_IS_INCLUDED_TRACE_RECORD_CALLOPS
 inline bool IsTraceRecordCallopsEnabled() {
   return IsExperimentEnabled<kExperimentIdTraceRecordCallops>();
diff --git a/src/core/lib/experiments/experiments.yaml b/src/core/lib/experiments/experiments.yaml
index a74b72dc62f..6cc3781f266 100644
--- a/src/core/lib/experiments/experiments.yaml
+++ b/src/core/lib/experiments/experiments.yaml
@@ -145,6 +145,11 @@
   expiry: 2024/12/01
   owner: vigneshbabu@google.com
   test_tags: ["endpoint_test", "flow_control_test"]
+- name: time_caching_in_party
+  description: Disable time caching in exec_ctx, and enable it only in a single party execution.
+  owner: ctiller@google.com
+  expiry: 2024/12/12
+  test_tags: []
 - name: trace_record_callops
   description: Enables tracing of call batch initiation and completion.
   expiry: 2024/12/01
diff --git a/src/core/lib/experiments/rollouts.yaml b/src/core/lib/experiments/rollouts.yaml
index e3a87d1f62b..661539b1029 100644
--- a/src/core/lib/experiments/rollouts.yaml
+++ b/src/core/lib/experiments/rollouts.yaml
@@ -98,6 +98,8 @@
   default: false
 - name: tcp_rcv_lowat
   default: false
+- name: time_caching_in_party
+  default: true
 - name: trace_record_callops
   default: true
 - name: unconstrained_max_quota_buffer_size
diff --git a/src/core/lib/iomgr/exec_ctx.h b/src/core/lib/iomgr/exec_ctx.h
index ce41e5b92b3..bcdb1a743d7 100644
--- a/src/core/lib/iomgr/exec_ctx.h
+++ b/src/core/lib/iomgr/exec_ctx.h
@@ -35,6 +35,7 @@
 #include <grpc/support/cpu.h>
 #include <grpc/support/time.h>
 
+#include "src/core/lib/experiments/experiments.h"
 #include "src/core/lib/gprpp/crash.h"
 #include "src/core/lib/gprpp/debug_location.h"
 #include "src/core/lib/gprpp/fork.h"
@@ -116,6 +117,11 @@ class GRPC_DLL ExecCtx : public latent_see::ParentScope {
   ExecCtx()
       : latent_see::ParentScope(GRPC_LATENT_SEE_METADATA("ExecCtx")),
         flags_(GRPC_EXEC_CTX_FLAG_IS_FINISHED) {
+#if !TARGET_OS_IPHONE
+    if (!IsTimeCachingInPartyEnabled()) {
+      time_cache_.emplace();
+    }
+#endif
     Fork::IncExecCtxCount();
     Set(this);
   }
@@ -126,6 +132,11 @@ class GRPC_DLL ExecCtx : public latent_see::ParentScope {
 
   explicit ExecCtx(uintptr_t fl, latent_see::Metadata* latent_see_metadata)
       : latent_see::ParentScope(latent_see_metadata), flags_(fl) {
+#if !TARGET_OS_IPHONE
+    if (!IsTimeCachingInPartyEnabled()) {
+      time_cache_.emplace();
+    }
+#endif
     if (!(GRPC_EXEC_CTX_FLAG_IS_INTERNAL_THREAD & flags_)) {
       Fork::IncExecCtxCount();
     }
@@ -195,23 +206,18 @@ class GRPC_DLL ExecCtx : public latent_see::ParentScope {
   Timestamp Now() { return Timestamp::Now(); }
 
   void InvalidateNow() {
-#if !TARGET_OS_IPHONE
-    time_cache_.InvalidateCache();
-#endif
+    if (time_cache_.has_value()) time_cache_->InvalidateCache();
   }
 
   void SetNowIomgrShutdown() {
-#if !TARGET_OS_IPHONE
     // We get to do a test only set now on this path just because iomgr
     // is getting removed and no point adding more interfaces for it.
-    time_cache_.TestOnlySetNow(Timestamp::InfFuture());
-#endif
+    TestOnlySetNow(Timestamp::InfFuture());
   }
 
   void TestOnlySetNow(Timestamp now) {
-#if !TARGET_OS_IPHONE
-    time_cache_.TestOnlySetNow(now);
-#endif
+    if (!time_cache_.has_value()) time_cache_.emplace();
+    time_cache_->TestOnlySetNow(now);
   }
 
   /// Gets pointer to current exec_ctx.
@@ -237,9 +243,7 @@ class GRPC_DLL ExecCtx : public latent_see::ParentScope {
   CombinerData combiner_data_ = {nullptr, nullptr};
   uintptr_t flags_;
 
-#if !TARGET_OS_IPHONE
-  ScopedTimeCache time_cache_;
-#endif
+  absl::optional<ScopedTimeCache> time_cache_;
 
 #if !defined(_WIN32) || !defined(_DLL)
   static thread_local ExecCtx* exec_ctx_;
diff --git a/src/core/lib/promise/party.cc b/src/core/lib/promise/party.cc
index c8bde2d198f..b8b6a899a48 100644
--- a/src/core/lib/promise/party.cc
+++ b/src/core/lib/promise/party.cc
@@ -269,6 +269,12 @@ void Party::RunPartyAndUnref(uint64_t prev_state) {
   DCHECK_EQ(prev_state & ~(kRefMask | kAllocatedMask), 0u)
       << "Party should have contained no wakeups on lock";
   prev_state |= kLocked;
+  absl::optional<ScopedTimeCache> time_cache;
+#if !TARGET_OS_IPHONE
+  if (IsTimeCachingInPartyEnabled()) {
+    time_cache.emplace();
+  }
+#endif
   for (;;) {
     uint64_t keep_allocated_mask = kAllocatedMask;
     // For each wakeup bit...
diff --git a/test/core/iomgr/timer_list_test.cc b/test/core/iomgr/timer_list_test.cc
index e3064c299ff..e3c98e83780 100644
--- a/test/core/iomgr/timer_list_test.cc
+++ b/test/core/iomgr/timer_list_test.cc
@@ -47,6 +47,8 @@ static void cb(void* arg, grpc_error_handle error) {
 }
 
 static void add_test(void) {
+  if (grpc_core::IsTimeCachingInPartyEnabled()) return;
+
   int i;
   grpc_timer timers[20];
   grpc_core::ExecCtx exec_ctx;
@@ -116,6 +118,8 @@ static void add_test(void) {
 
 // Cleaning up a list with pending timers.
 void destruction_test(void) {
+  if (grpc_core::IsTimeCachingInPartyEnabled()) return;
+
   grpc_timer timers[5];
   grpc_core::ExecCtx exec_ctx;
 
@@ -173,6 +177,8 @@ void destruction_test(void) {
 //  4) Shuts down the timer list
 // https://github.com/grpc/grpc/issues/15904
 void long_running_service_cleanup_test(void) {
+  if (grpc_core::IsTimeCachingInPartyEnabled()) return;
+
   grpc_timer timers[4];
   grpc_core::ExecCtx exec_ctx;
 
diff --git a/test/core/security/credentials_test.cc b/test/core/security/credentials_test.cc
index 721a02f6e33..3731f5ca189 100644
--- a/test/core/security/credentials_test.cc
+++ b/test/core/security/credentials_test.cc
@@ -2492,6 +2492,7 @@ TEST_F(TokenFetcherCredentialsTest, Basic) {
   ExecCtx exec_ctx;
   creds_->AddResult(MakeToken("foo", kExpirationTime));
   // First request will trigger a fetch.
+  LOG(INFO) << "First request";
   auto state = RequestMetadataState::NewInstance(
       absl::OkStatus(), "authorization: foo", /*expect_delay=*/true);
   state->RunRequestMetadataTest(creds_.get(), kTestUrlScheme, kTestAuthority,
@@ -2499,6 +2500,7 @@ TEST_F(TokenFetcherCredentialsTest, Basic) {
   EXPECT_EQ(creds_->num_fetches(), 1);
   // Second request while fetch is still outstanding will be delayed but
   // will not trigger a new fetch.
+  LOG(INFO) << "Second request";
   state = RequestMetadataState::NewInstance(
       absl::OkStatus(), "authorization: foo", /*expect_delay=*/true);
   state->RunRequestMetadataTest(creds_.get(), kTestUrlScheme, kTestAuthority,
@@ -2507,6 +2509,7 @@ TEST_F(TokenFetcherCredentialsTest, Basic) {
   // Now tick to finish the fetch.
   event_engine_->TickUntilIdle();
   // Next request will be served from cache with no delay.
+  LOG(INFO) << "Third request";
   state = RequestMetadataState::NewInstance(
       absl::OkStatus(), "authorization: foo", /*expect_delay=*/false);
   state->RunRequestMetadataTest(creds_.get(), kTestUrlScheme, kTestAuthority,
@@ -2519,6 +2522,7 @@ TEST_F(TokenFetcherCredentialsTest, Basic) {
   // Next request will trigger a new fetch but will still use the
   // cached token.
   creds_->AddResult(MakeToken("bar"));
+  LOG(INFO) << "Fourth request";
   state = RequestMetadataState::NewInstance(
       absl::OkStatus(), "authorization: foo", /*expect_delay=*/false);
   state->RunRequestMetadataTest(creds_.get(), kTestUrlScheme, kTestAuthority,
@@ -2526,6 +2530,7 @@ TEST_F(TokenFetcherCredentialsTest, Basic) {
   EXPECT_EQ(creds_->num_fetches(), 2);
   event_engine_->TickUntilIdle();
   // Next request will use the new data.
+  LOG(INFO) << "Fifth request";
   state = RequestMetadataState::NewInstance(
       absl::OkStatus(), "authorization: bar", /*expect_delay=*/false);
   state->RunRequestMetadataTest(creds_.get(), kTestUrlScheme, kTestAuthority,