It’s difficult to narrow down the ultimate Mexican food in the restaurant capital of a Hispanic-flavored town like San Antonio , but several spots float to the top of the River Walk  scene due to their long-standing reputation for consistent quality and service.
Among them are Casa Rio (430 E. Commerce St., 210/225-6718, www.casa-rio.com , $8–19). Considered the first-ever restaurant on the River Walk, this venerable institution is a great place to get started on your Tex-Mex adventure in San Antonio . Interior walls and patio umbrellas radiate festive colors, complementing the equally tantalizing food. You can’t go wrong with the basics here—their beef tacos, chicken enchiladas, pork tamales, and cheesy quesadillas are perfecto, especially when accompanied by a refreshing margarita or Mexican cerveza. Snag a seat on the patio for optimal people-watching and ambiance, and be sure to arrive early since the standard wait at noon and 6 p.m. is typically 30–45 minutes.
Another classic Tex-Mex spot on the riverbank is Rio Rio Cantina (421 E. Commerce St., 210/228-8462, www.rioriocantina.com , $9–21). Bring your appetite, since the portions here are enormous. Fortunately, they’re tasty, too, especially the chicken enchiladas with green salsa, the camarones Yucateco (spicy shrimp) and even the standard fajita plate, containing enough beef and chicken to feed an entire crew on one of the passing river barges. Kids will love the quesadillas, and their parents will appreciate the noisy chatter drowning out their incessant questions about the pervasive pigeons.
Those looking for a step up from the standard Tex-Mex fare should head directly to the remarkable Acenar (146 E. Houston St., 210/222-2362, www.acenar.com , $12–28). This is one of the largest restaurants on the River Walk , and its multiple levels and tables are consistently packed with diners enjoying the stellar view and stunning Mexican food with a distinctive twist. Tacos are packed with unconventional fillings like crab and oyster, and any dish with the savory mole sauce is magnificent. Accompany your meal with one of Acenar’s signature “hand-shaken” margaritas and try to save room for the exquisite tres leches cake or coconut flan.
Just because you’re in proximity to the Rio Grande doesn’t mean you have to eat Mexican food all the time. At least one meal a day can be set aside for other gastronomical considerations, and in a touristy area like the River Walk , the best bet is a good ol’ American-style restaurant with a local twist.
One of the most popular destinations for this kind of family-friendly fare is Zuni Grill (223 Losoya St., 210/227-0864, www.zunigrill.com , $10–22). Splashes of bright colors are everywhere, from the mosaic tiles on the tables to the brightly colored walls inside. Request a seat on the patio for a wonderful view of the river, and order a signature Cactus ’Rita while you’re waiting for your entrée. Noteworthy options include a glazed pork loin, grilled salmon, and chicken quesadillas. Incidentally, this is one of the few restaurants on the River Walk  that serves breakfast.
For a fancy dining experience, consider Boudro’s (421 E. Commerce St., 210/224-8484, www.boudros.com , $12–32). Not many places on the river can entice locals to wade through the throngs of walkers, but since Boudro’s does, be sure to call ahead for a reservation. If you’re looking for a little local flavor, start with a prickly pear margarita accompanied by chips and fresh-made guacamole prepared at your table. Entrées run the gamut from seafood to steaks to upscale Southwestern dishes, and Boudro’s desserts (bread pudding, flan, créme brûlée) are legendary.
Another upscale eatery drawing townies through its doors is Biga on the Banks (203 S. St. Mary’s St., 210/225-0722, www.biga.com , $13–34). Located off the trampled path in the city’s former central library, Biga’s has established a reputation for serving some of the finest cuisine in the state. (Gourmet magazine named it one of the top five restaurants in Texas.) The menu is brimming with savory items, including smoked pork chops, seared tuna, roasted lamb, grilled steaks, and wild game. Many dishes are accompanied by bold touches such as curry sauces and foie gras. Be sure to make reservations to ensure a seat at this exquisite establishment.
The River Walk  would be an incomplete Texas tradition without a barbecue restaurant in the mix. Some of the best San Antonio  has to offer is at The County Line (111 W. Crockett #104, 210/229-1941, $9–14). This is authentic Texas-style ’cue, so load up on tender brisket, meaty beef ribs, and flavorful sausage, accompanied by classic sides like potato salad and cole slaw. Wash it all down with a cold Shiner Bock or Dr Pepper.