diff --git a/ipwb/__main__.py b/ipwb/__main__.py
index 42da2d3d..84201529 100644
--- a/ipwb/__main__.py
+++ b/ipwb/__main__.py
@@ -58,9 +58,14 @@ def check_args_replay(args):
         print(f'Proxying to {args.proxy}')
         proxy = args.proxy
 
+    port = replay.IPWBREPLAY_PORT
+    if hasattr(args, 'port') and args.port is not None:
+        print(f'Using custom port {args.port} for replay.')
+        port = args.port
+
     # TODO: add any other sub-arguments for replay here
     if supplied_index_parameter:
-        replay.start(cdxj_file_path=args.index, proxy=proxy)
+        replay.start(cdxj_file_path=args.index, proxy=proxy, port=port)
     else:
         print('ERROR: An index file must be specified if not piping, e.g.,')
         print(("> ipwb replay "
@@ -133,6 +138,12 @@ def check_args(args_in):
         help='Proxy URL',
         metavar='<host:port>',
         nargs='?')
+    replay_parser.add_argument(
+        '-p', '--port',
+        help='Custom Port',
+        type=int,
+        default=util.IPWBREPLAY_PORT
+    )
     replay_parser.set_defaults(func=check_args_replay,
                                onError=replay_parser.print_help)
 
diff --git a/ipwb/replay.py b/ipwb/replay.py
index dd6ae15e..d83fa427 100755
--- a/ipwb/replay.py
+++ b/ipwb/replay.py
@@ -1047,12 +1047,15 @@ def get_cdxj_line_binary_search(
     return line_found
 
 
-def start(cdxj_file_path, proxy=None):
+def start(cdxj_file_path, proxy=None, port=IPWBREPLAY_PORT):
     host_port = ipwb_utils.get_ipwb_replay_config()
     app.proxy = proxy
 
+    # Retain port for subsequent runs
+    ipwb_utils.set_ipwb_replay_config(IPWBREPLAY_HOST, port)
+
     if not host_port:
-        ipwb_utils.set_ipwb_replay_config(IPWBREPLAY_HOST, IPWBREPLAY_PORT)
+        host_port = (IPWBREPLAY_HOST, port)
 
     # This will throw an exception if daemon is not available.
     ipwb_utils.check_daemon_is_alive()
@@ -1062,9 +1065,9 @@ def start(cdxj_file_path, proxy=None):
 
     try:
         print((f'IPWB replay started on '
-               f'http://{IPWBREPLAY_HOST}:{IPWBREPLAY_PORT}'))
+               f'http://{host_port[0]}:{host_port[1]}'))
 
-        app.run(host='0.0.0.0', port=IPWBREPLAY_PORT)
+        app.run(host='0.0.0.0', port=host_port[1])
     except gaierror:
         print('Detected no active Internet connection.')
         print('Overriding to use default IP and port configuration.')