diff --git a/validator/coordinator/src/main/java/tech/pegasys/teku/validator/coordinator/ValidatorApiHandler.java b/validator/coordinator/src/main/java/tech/pegasys/teku/validator/coordinator/ValidatorApiHandler.java
index ee3ed44e253..96bc6504c1c 100644
--- a/validator/coordinator/src/main/java/tech/pegasys/teku/validator/coordinator/ValidatorApiHandler.java
+++ b/validator/coordinator/src/main/java/tech/pegasys/teku/validator/coordinator/ValidatorApiHandler.java
@@ -13,7 +13,6 @@
 
 package tech.pegasys.teku.validator.coordinator;
 
-import static java.util.Collections.emptyMap;
 import static java.util.stream.Collectors.toList;
 import static tech.pegasys.teku.datastructures.util.BeaconStateUtil.compute_epoch_at_slot;
 import static tech.pegasys.teku.datastructures.util.BeaconStateUtil.compute_start_slot_at_epoch;
@@ -147,19 +146,20 @@ public SafeFuture<Optional<GenesisData>> getGenesisData() {
   @Override
   public SafeFuture<Map<BLSPublicKey, Integer>> getValidatorIndices(
       final List<BLSPublicKey> publicKeys) {
-    return SafeFuture.completedFuture(
-        combinedChainDataClient
-            .getBestState()
-            .map(
-                state -> {
-                  final Map<BLSPublicKey, Integer> results = new HashMap<>();
-                  publicKeys.forEach(
-                      publicKey ->
-                          ValidatorsUtil.getValidatorIndex(state, publicKey)
-                              .ifPresent(index -> results.put(publicKey, index)));
-                  return results;
-                })
-            .orElse(emptyMap()));
+    return SafeFuture.of(
+        () ->
+            combinedChainDataClient
+                .getBestState()
+                .map(
+                    state -> {
+                      final Map<BLSPublicKey, Integer> results = new HashMap<>();
+                      publicKeys.forEach(
+                          publicKey ->
+                              ValidatorsUtil.getValidatorIndex(state, publicKey)
+                                  .ifPresent(index -> results.put(publicKey, index)));
+                      return results;
+                    })
+                .orElseThrow(() -> new IllegalStateException("Head state is not yet available")));
   }
 
   @Override
diff --git a/validator/coordinator/src/test/java/tech/pegasys/teku/validator/coordinator/ValidatorApiHandlerTest.java b/validator/coordinator/src/test/java/tech/pegasys/teku/validator/coordinator/ValidatorApiHandlerTest.java
index c46eed07090..301fc4fb053 100644
--- a/validator/coordinator/src/test/java/tech/pegasys/teku/validator/coordinator/ValidatorApiHandlerTest.java
+++ b/validator/coordinator/src/test/java/tech/pegasys/teku/validator/coordinator/ValidatorApiHandlerTest.java
@@ -14,7 +14,6 @@
 package tech.pegasys.teku.validator.coordinator;
 
 import static java.util.Collections.emptyList;
-import static java.util.Collections.emptyMap;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.ArgumentMatchers.any;
@@ -526,12 +525,14 @@ public void sendAggregateAndProof_shouldPostAggregateAndProof() {
   }
 
   @Test
-  void getValidatorIndices_shouldReturnEmptyMapWhenBestStateNotAvailable() {
+  void getValidatorIndices_shouldThrowExceptionWhenBestStateNotAvailable() {
     when(chainDataClient.getBestState()).thenReturn(Optional.empty());
 
+    // The validator client needs to be able to differentiate between the state not yet being loaded
+    // and the requested validators not existing so it doesn't skip scheduling duties.
     assertThatSafeFuture(
             validatorApiHandler.getValidatorIndices(List.of(dataStructureUtil.randomPublicKey())))
-        .isCompletedWithValue(emptyMap());
+        .isCompletedExceptionallyWith(IllegalStateException.class);
   }
 
   @Test