diff --git a/java/google/registry/tmch/TmchCertificateAuthority.java b/java/google/registry/tmch/TmchCertificateAuthority.java
index a3ec73f60..c21437c1b 100644
--- a/java/google/registry/tmch/TmchCertificateAuthority.java
+++ b/java/google/registry/tmch/TmchCertificateAuthority.java
@@ -20,6 +20,7 @@ import static google.registry.config.RegistryConfig.getSingletonCacheRefreshDura
 import static google.registry.util.ResourceUtils.readResourceUtf8;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.cache.CacheLoader;
 import com.google.common.cache.LoadingCache;
@@ -119,7 +120,8 @@ public final class TmchCertificateAuthority {
                 }});
 
   @NonFinalForTesting
-  private static Clock clock = new SystemClock();
+  @VisibleForTesting
+  public static Clock clock = new SystemClock();
 
   /**
    * Check that {@code cert} is signed by the ICANN TMCH CA root and not revoked.
diff --git a/javatests/google/registry/flows/EppLifecycleDomainApplicationTest.java b/javatests/google/registry/flows/EppLifecycleDomainApplicationTest.java
index b9e043ab9..24fcc0fc3 100644
--- a/javatests/google/registry/flows/EppLifecycleDomainApplicationTest.java
+++ b/javatests/google/registry/flows/EppLifecycleDomainApplicationTest.java
@@ -20,6 +20,7 @@ import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSortedMap;
 import google.registry.model.registry.Registry.TldState;
 import google.registry.testing.AppEngineRule;
+import google.registry.tmch.TmchCertificateAuthority;
 import google.registry.util.DateTimeUtils;
 import org.joda.time.DateTime;
 import org.junit.Before;
@@ -42,6 +43,8 @@ public class EppLifecycleDomainApplicationTest extends EppTestCase {
 
   @Before
   public void initTld() {
+    // Setting the clock used for SignedMark signature validity.
+    TmchCertificateAuthority.clock = () -> DateTime.parse("2015-01-01TZ");
     createTld("example", ImmutableSortedMap.of(
         DateTimeUtils.START_OF_TIME, TldState.SUNRISE,
         START_OF_GA, TldState.GENERAL_AVAILABILITY));
diff --git a/javatests/google/registry/flows/EppLifecycleDomainTest.java b/javatests/google/registry/flows/EppLifecycleDomainTest.java
index 44e4dbcaf..4ae181c40 100644
--- a/javatests/google/registry/flows/EppLifecycleDomainTest.java
+++ b/javatests/google/registry/flows/EppLifecycleDomainTest.java
@@ -45,6 +45,7 @@ import google.registry.model.registry.Registry;
 import google.registry.model.registry.Registry.TldState;
 import google.registry.model.reporting.HistoryEntry.Type;
 import google.registry.testing.AppEngineRule;
+import google.registry.tmch.TmchCertificateAuthority;
 import java.util.Objects;
 import java.util.Optional;
 import org.joda.money.Money;
@@ -65,6 +66,8 @@ public class EppLifecycleDomainTest extends EppTestCase {
 
   @Before
   public void initTld() {
+    // Setting the clock used for SignedMark signature validity.
+    TmchCertificateAuthority.clock = () -> DateTime.parse("2015-01-01TZ");
     createTlds("example", "tld");
   }
 
diff --git a/javatests/google/registry/flows/domain/DomainCreateFlowTest.java b/javatests/google/registry/flows/domain/DomainCreateFlowTest.java
index e438fe9a5..71b23b1ec 100644
--- a/javatests/google/registry/flows/domain/DomainCreateFlowTest.java
+++ b/javatests/google/registry/flows/domain/DomainCreateFlowTest.java
@@ -151,6 +151,7 @@ import google.registry.model.reporting.DomainTransactionRecord.TransactionReport
 import google.registry.model.reporting.HistoryEntry;
 import google.registry.monitoring.whitebox.EppMetric;
 import google.registry.testing.TaskQueueHelper.TaskMatcher;
+import google.registry.tmch.TmchCertificateAuthority;
 import java.util.Map;
 import org.joda.money.CurrencyUnit;
 import org.joda.money.Money;
@@ -172,6 +173,8 @@ public class DomainCreateFlowTest extends ResourceFlowTestCase<DomainCreateFlow,
 
   @Before
   public void initCreateTest() {
+    // Setting the clock used for SignedMark signature validity.
+    TmchCertificateAuthority.clock = () -> DateTime.parse("2015-01-01TZ");
     createTld("tld");
     persistResource(
         Registry.get("tld")
diff --git a/javatests/google/registry/tools/UpdateSmdCommandTest.java b/javatests/google/registry/tools/UpdateSmdCommandTest.java
index 9900b4bc6..e3fb8b820 100644
--- a/javatests/google/registry/tools/UpdateSmdCommandTest.java
+++ b/javatests/google/registry/tools/UpdateSmdCommandTest.java
@@ -73,6 +73,8 @@ public class UpdateSmdCommandTest extends CommandTestCase<UpdateSmdCommand> {
 
   @Before
   public void init() {
+    // Setting the clock used for SignedMark signature validity.
+    TmchCertificateAuthority.clock = () -> DateTime.parse("2015-01-01TZ");
     inject.setStaticField(Ofy.class, "clock", clock);
     createTld("xn--q9jyb4c");
     clock.advanceOneMilli();