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.