The best way to get here is by car, taking the expressway voie express Nantes-Brest N165 and getting off at Crach,la trinite sur mer exit; follow first the D28 and then the D781 to la Trinite sur Mer.
bus you take the minimum service TIM =transports interurbain du Morbihan lines 1 or 18.
There is a Trinibus for the months of July and August only, taking you to city center, beaches, port, and villages around it every day of the week. service is Free. The transport doing it is MAury-transports.com
email for info firstname.lastname@example.org
or the mayors office of La Trinite sur Mer
You have parking for your car, La Vigie, ure Mané Rohr or along the cours des quais on the harbor ar the best areas. the first one is free parking the other is metered or blue zone limited parking time.
Taxis are available such as www.taxis-trinitains.com
by train you could come from Paris montparnasse to Auray and get on the TIM buses above indicated to take you here. You can try different scenarios with the Brittany all inclusive public transportation site Breizhgo
nice way to see the town and the beautiful boats plus going up to the upper city ,give a feeling for the whole and you can walk and enjoy the rest.
It can even takes you to very nearby Carnac, UNESCO World Heritage site for its monolithic stones alignment.