Santa Semana how long does it last

Depends on your own preferences. If you love mingling with lots of people, and you want to interact with locals, then come down for the Easter long weekend. What happens is that any lull in their usual booking of foreign tourists, will be filled with local tourists. Some hotels traditionally leave space for the locals. Note that local tourists during this peak time pay more than the tourists -- that get bulk rates through the tour operators.

Note that Semana Santa is mainly the long weekend of Thursday through Sunday. That is the peak travel time for Dominicans, with public access beaches and resorts booked with a large number of locals. Note that many hotels are already fully booked with their foreign tourist allotments, so may not be the case of all resorts. Whatever, at those with restricted beach access it will just be business as usual.

Other peak times are Christmas holidays and July and August. Of course, January, February and March are already peak times for foreign tourists fleeing the cold weather.