Kuchenbar
Great anytime desserts, especially in sidewalk weather.
Stadtamhof
Stadtamhof is an island area in the middle of the Danube (or at least its canals) close to where the river Regen flows into it. You most famously enter Stadtamhof via the Steinerne Brücke (Stone Bridge) but there are also other foot bridges onto the islands. Car traffic is permitted only via the Eiserne Brücke (Iron Bridge) but that won’t put you close to the dining action in Stadtamhof.
Early Bird
It’s fancier than you think.
Alte Linde
If you get the right table, it’s Regensburg’s prettiest Biergarten.