Kamianiec is about 40 km north of Brest on the P44 road. From Brest, local buses run to Kamianiec several times daily; the journey takes about an hour. By car from Brest the trip is straightforward on a good road.
From Minsk, the journey involves getting to Brest first (about 3.5 hours by fast train) and then connecting to Kamianiec. Most visitors combine the tower with the Belavezhskaya Pushcha national park and make it a day trip or overnight from Brest.
Note: Travel to Belarus requires up-to-date visa and entry information given the current political situation. Check your government's travel advisories before planning a trip.