diff --git a/yarn-project/archiver/src/modules/l1_synchronizer.ts b/yarn-project/archiver/src/modules/l1_synchronizer.ts
index 092df4b083f8..33afde395721 100644
--- a/yarn-project/archiver/src/modules/l1_synchronizer.ts
+++ b/yarn-project/archiver/src/modules/l1_synchronizer.ts
@@ -3,6 +3,7 @@ import { EpochCache } from '@aztec/epoch-cache';
 import { InboxContract, RollupContract } from '@aztec/ethereum/contracts';
 import type { L1BlockId } from '@aztec/ethereum/l1-types';
 import type { ViemPublicClient, ViemPublicDebugClient } from '@aztec/ethereum/types';
+import { asyncPool } from '@aztec/foundation/async-pool';
 import { maxBigint } from '@aztec/foundation/bigint';
 import { BlockNumber, CheckpointNumber, EpochNumber } from '@aztec/foundation/branded-types';
 import { Buffer32 } from '@aztec/foundation/buffer';
@@ -333,17 +334,20 @@ export class ArchiverL1Synchronizer implements Traceable {
 
       const checkpointsToUnwind = localPendingCheckpointNumber - provenCheckpointNumber;
 
-      const checkpointPromises = Array.from({ length: checkpointsToUnwind })
-        .fill(0)
-        .map((_, i) => this.store.getCheckpointData(CheckpointNumber(i + pruneFrom)));
-      const checkpoints = await Promise.all(checkpointPromises);
-
-      const blockPromises = await Promise.all(
-        checkpoints
-          .filter(isDefined)
-          .map(cp => this.store.getBlocksForCheckpoint(CheckpointNumber(cp.checkpointNumber))),
+      // Fetch checkpoints and blocks in bounded batches to avoid unbounded concurrent
+      // promises when the gap between local pending and proven checkpoint numbers is large.
+      const BATCH_SIZE = 10;
+      const indices = Array.from({ length: checkpointsToUnwind }, (_, i) => CheckpointNumber(i + pruneFrom));
+      const checkpoints = (await asyncPool(BATCH_SIZE, indices, idx => this.store.getCheckpointData(idx))).filter(
+        isDefined,
       );
-      const newBlocks = blockPromises.filter(isDefined).flat();
+      const newBlocks = (
+        await asyncPool(BATCH_SIZE, checkpoints, cp =>
+          this.store.getBlocksForCheckpoint(CheckpointNumber(cp.checkpointNumber)),
+        )
+      )
+        .filter(isDefined)
+        .flat();
 
       // Emit an event for listening services to react to the chain prune
       this.events.emit(L2BlockSourceEvents.L2PruneUnproven, {