Although we planned drive ourselves in Croatia, we opted not to keep the car we’d rented in Montenegro for that trip. My reasoning was 1) we’d avoid cross border charges; and 2) we didn’t want a car for our days in Old Dubrovnik anyway since parking is nonexistent in the old town. The best option appeared to be a motor coach. I bought tickets ahead of time on GetByBus at https://getbybus.com/en/ for 483.5 Croatian kuna ($42.5o) for 2 tickets, tax included. A print-out of the ticket is required and the drive is about 2 hours. We had only one brief stop at a town along the way.
The Kotor bus station is close to old town, but on the opposite side from our apartment. Marjana kindly offered to drive us, and would not accept payment. The bus station is relatively small and easy to navigate. There’s no need to arrive extra early, but do know there’s a station fee that has to be paid before you can board a bus. This wasn’t included in our ticket fee nor did I see any mention ahead of time. This caused a momentary panic when the driver asked to see the receipt for our local payment, but a quick dash inside (and a teller who waved me to the front of the short line) resolved the problem.
The bus itself was a comfortable tour bus/Greyhound-style motor coach. Free wi-fi was supposedly included, but we both had trouble connecting. The border crossing was easy with the driver collecting our passports for a brief stop. The bus stop in Dubrovnik is right by the cruise port. We caught a cab to the Old Dubrovnik main gaten this time because of our luggage, but there’s a bus stop just up on the main road by the newsstand where you can also buy a local bus ticket.