Air Mauritius operates daily flights between Sir Seewoosagur Ramgoolam International Airport and Sir Gaëtan Duval Airport (RRG) on Rodrigues. The flight takes about 1 hour 30 minutes. Book in advance during July–August and around Mauritian public holidays, when seats fill quickly.
The MV Mauritius Trochetia passenger-cargo ferry operates between Port Louis and Port Mathurin two to three times per month. The crossing takes roughly 36 hours each way across open ocean, and conditions can be rough. It's cheap, an experience in itself, and worth it if you have time — check the Mauritius Shipping Corporation website for the current schedule.