Before you can get to Abrolhos, you must first go to Caravelas. Here you will find a number of tour operators authorized by IBAMA to sail to the archipelago. The cost per person for a day-trip is around R$220 about USD 140. Check the page for Caravelas for instructions on how to get to Caravelas.
Once in Caravelas, you can only get to Abrolhos by boat. Your choices are:
Fishing boat
If you go on a fishing boat it will take around 6 hours to get there. You will be forced on a overnight stay.Catamarã
Takes around 3h30min and you have the choice to stay overnight.Speed boat
Around 1h30min depending on sea conditions. It is a one-day trip.