Bushmills is around two miles from the Causeway visitor area according to the National Trust. The Bushmills Inn gives a town-based comparison for returning to a meal after the coast, with less road travel than the other two bases.
Good for: A short break focused on the Causeway and its immediate area.
Before you choose: Two miles does not establish a suitable roadside walk. Choose the actual bus, drive or walking route and return arrangement, and distinguish visitor-centre parking from separate walking access.
Portrush adds beaches and a resort-town evening to the trip. Portrush Adelphi illustrates this choice for visitors who want the overnight base to have a different character from the Causeway visit. Plan the coastal outing as a separate road or dated bus journey.
Good for: Visitors combining one Causeway day with time in a seaside town.
Before you choose: It is farther west than Bushmills and requires a transfer. Check the seasonal service and stop closest to the hotel before treating a coastal bus route as an all-day, all-year guarantee.
Ballycastle is around 13 miles from the Causeway in the National Trust's directions. Marine Hotel provides a seafront-town comparison when the rest of your trip lies eastward. It works best when Ballycastle itself is part of the reason to stay.
Good for: A longer coast trip that gives Ballycastle its own time.
Before you choose: This is the longest approach of the three bases. Keep the Causeway a distinct excursion and check the return transport. Do not add another exposed coastal activity simply to justify the journey.