diff --git a/swh/journal/cli.py b/swh/journal/cli.py
--- a/swh/journal/cli.py
+++ b/swh/journal/cli.py
@@ -177,9 +177,12 @@
                    '(deprecated, use the config file instead)')
 @click.option('--exclude-sha1-file', default=None, type=click.File('rb'),
               help='File containing a sorted array of hashes to be excluded.')
+@click.option('--check-dst/--no-check-dst', default=True,
+              help='Check whether the destination contains the object before '
+                   'copying.')
 @click.pass_context
 def content_replay(ctx, max_messages,
-                   brokers, prefix, group_id, exclude_sha1_file):
+                   brokers, prefix, group_id, exclude_sha1_file, check_dst):
     """Fill a destination Object Storage (typically a mirror) by reading a Journal
     and retrieving objects from an existing source ObjStorage.
 
@@ -197,6 +200,10 @@
     and it must be sorted.
     This file will not be fully loaded into memory at any given time,
     so it can be arbitrarily large.
+
+    `--check-dst` sets whether the replayer should check in the destination
+    ObjStorage before copying an object. You can turn that off if you know
+    you're copying to an empty ObjStorage.
     """
     logger = logging.getLogger(__name__)
     conf = ctx.obj['config']
@@ -226,10 +233,10 @@
     client = get_journal_client(
         ctx, brokers=brokers, prefix=prefix, group_id=group_id,
         max_messages=max_messages, object_types=('content',))
-    worker_fn = functools.partial(process_replay_objects_content,
-                                  src=objstorage_src,
-                                  dst=objstorage_dst,
-                                  exclude_fn=exclude_fn)
+    worker_fn = functools.partial(
+        process_replay_objects_content,
+        src=objstorage_src, dst=objstorage_dst, exclude_fn=exclude_fn,
+        check_dst=check_dst)
 
     if notify:
         notify('READY=1')
diff --git a/swh/journal/replay.py b/swh/journal/replay.py
--- a/swh/journal/replay.py
+++ b/swh/journal/replay.py
@@ -322,7 +322,7 @@
 
 
 def process_replay_objects_content(all_objects, *, src, dst,
-                                   exclude_fn=None):
+                                   exclude_fn=None, check_dst=True):
     """
     Takes a list of records from Kafka (see
     :py:func:`swh.journal.client.JournalClient.process`) and copies them
@@ -392,6 +392,11 @@
                              hash_to_hex(obj_id))
                 statsd.increment(CONTENT_OPERATIONS_METRIC,
                                  tags={"decision": "excluded"})
+            elif check_dst and obj_id in dst:
+                nb_skipped += 1
+                logger.debug('skipped %s (in dst)', hash_to_hex(obj_id))
+                statsd.increment(CONTENT_OPERATIONS_METRIC,
+                                 tags={"decision": "in_dst"})
             else:
                 vol.append(copy_object(obj_id, src, dst))
                 statsd.increment(CONTENT_OPERATIONS_METRIC,
diff --git a/swh/journal/tests/test_cli.py b/swh/journal/tests/test_cli.py
--- a/swh/journal/tests/test_cli.py
+++ b/swh/journal/tests/test_cli.py
@@ -272,3 +272,64 @@
         else:
             assert sha1 in objstorages['dst'], sha1
             assert objstorages['dst'].get(sha1) == content
+
+
+NUM_CONTENTS_DST = 5
+
+
+@_patch_objstorages(['src', 'dst'])
+@pytest.mark.parametrize("check_dst,expected_copied,expected_in_dst", [
+    (True, NUM_CONTENTS - NUM_CONTENTS_DST, NUM_CONTENTS_DST),
+    (False, NUM_CONTENTS, 0),
+])
+def test_replay_content_check_dst(
+        objstorages,
+        storage,
+        kafka_prefix: str,
+        kafka_server: Tuple[Popen, int],
+        check_dst: bool,
+        expected_copied: int,
+        expected_in_dst: int,
+        caplog):
+    (_, kafka_port) = kafka_server
+    kafka_prefix += '.swh.journal.objects'
+
+    contents = _fill_objstorage_and_kafka(
+        kafka_port, kafka_prefix, objstorages)
+
+    for i, (sha1, content) in enumerate(contents.items()):
+        if i >= NUM_CONTENTS_DST:
+            break
+
+        objstorages['dst'].add(content, obj_id=sha1)
+
+    caplog.set_level(logging.DEBUG, 'swh.journal.replay')
+
+    result = invoke(False, [
+        'content-replay',
+        '--broker', '127.0.0.1:%d' % kafka_port,
+        '--group-id', 'test-cli-consumer',
+        '--prefix', kafka_prefix,
+        '--max-messages', str(NUM_CONTENTS),
+        '--check-dst' if check_dst else '--no-check-dst',
+    ])
+    expected = r'Done.\n'
+    assert result.exit_code == 0, result.output
+    assert re.fullmatch(expected, result.output, re.MULTILINE), result.output
+
+    copied = 0
+    in_dst = 0
+    for record in caplog.records:
+        logtext = record.getMessage()
+        if 'copied' in logtext:
+            copied += 1
+        elif 'in dst' in logtext:
+            in_dst += 1
+
+    assert (copied == expected_copied and in_dst == expected_in_dst), (
+        "Unexpected amount of objects copied, see the captured log for details"
+    )
+
+    for (sha1, content) in contents.items():
+        assert sha1 in objstorages['dst'], sha1
+        assert objstorages['dst'].get(sha1) == content