Make Sure You Pay Your Montenegro Tourist Tax
If you’re visiting Montenegro as a tourist, it’s important that you register with the authorities and pay your tourist tax. Not doing so could result in a fine when you leave the country.
We’ve been told that this is strictly enforced, so you need to make sure you don’t skip it. If you’re staying in a hotel or apartment, the owner should do this for you. You’ll likely have to pay the tax separately from your accommodation costs.

You need to register and pay the tax within 24 hours of arriving at your destination. We had booked a stay at Old Town Square Apartment and when the owner met us she took us directly to register ourselves. As we had booked three nights, we had to pay 6 EUR – 1 EUR per person per night.
After our initial 3-day stay, we decided to stay another 3 days, so had to re-register and pay the tax for the extra nights. We later traveled to Budva, so also had to register there and pay the tax.

Above you can see the Registration of Residence office in Kotor. It’s around 100 meters from the main gate of the old town.
You’ll need to show your passport or ID card, and give the address you’re staying at and the number of nights you’re staying. You then get two copies of the registration – one for you and one for the owner of the property.

Keep this document safe, as you may need to show it to immigration when you leave the country. I’ll update this when we leave the country to let you know if we were asked for it or not.
Update: No, we were not asked to show it. We've now left Montenegro three times and never been asked for it.
Where to stay in Kotor

We stayed at Old Town Square Kotor Apartment for our first three nights and then moved to Boskovic Apartment for the next three nights. They have the same owner. We wanted to stay at the first apartment but it had already been booked by someone else.
If you prefer to stay in a hotel, check out the excellent choices at Agoda Kotor.