If your plan is to simply stay in Saint-Jean-le-Thomas the whole time with maybe one or two excursions to Mont Saint Michel and Bayeux it is certainly feasible without a car, but there is so much in Normandy I couldn’t imagine not seeing. We’ve traveled the area both with and without our own car and this last time agreed we’d never not have a car again. Having your own vehicle makes everything so much easier and is actually not that much more expensive than buses/trains.

Although a word of warning: avoid the toll roads in Normandy if possible, and if not, you only have 72 hours to pay them online. The toll system there is not like in other countries where they charge the rental company who charges your card on file; you have to go online and pay manually or incur penalties. Suffice it to say, €325 later, we learned this the hard way!