Only one full restaurant sits inside Rennes T1: Trib's
Rennes-Saint-Jacques Airport only lists Trib's as the terminal-side restaurant in T1, so this is basically your landside food stop before security. It sits in the main terminal (not in the boarding area) and the airport pairs it on the website with Bread & Co, which is explicitly listed as the boarding-area option.
The official description says Trib's serves snacks, hot dishes, sandwiches, salads, cookies, and pastries, so expect more than just coffee and a croissant. Think grab-and-go sandwiches and salads if you need something quick, plus at least a couple of plated hot options if you have time to sit. Prices aren’t published, but French regional airports usually sit in the mid-range: more than a boulangerie in town, less than a Paris CDG brasserie.
Since Bread & Co is listed in the boarding area and Trib’s is not, plan on Trib’s for a proper bite while you’re still landside in T1. That setup works well if you’re dropping a rental car or checking in early and want real food before you queue for security. Once you cross to the boarding side, you’re basically down to Bread & Co for anything else.
With no published hours for Trib’s on the Rennes airport site, assume typical regional-airport timing: opening a bit before the first bank of departures and closing around the last evening flights. If you’re on a very early or late service from RNS, have a backup snack in your bag in case Trib’s isn’t running full service when you pass through T1.
Tip: if you care more about an actual meal than one last espresso, eat at Trib’s in the terminal before security and use Bread & Co in the boarding area only as a top-up stop for coffee or a pastry.