Trebinje eats well for a small town. Local Herzegovinian cuisine leans heavy on grilled meats, dairy and the simple Mediterranean influences that have travelled up from the coast: lamb on the spit, the local sušeno meso (air-dried ham, like an Italian prosciutto), young cheese, fresh figs in season, and the Vranac red wine from the Tvrdoš and other regional monasteries. The cafes around the old town do good Bosnian coffee — thick, sweet, served with a Turkish delight.
For a quick lunch, the ćevapi (small grilled minced-meat fingers) at any of the kafanas on Mostarska street are reliable. For something more substantial, head to a restaurant in the old town or at the river bridge.