If you don't mind eating food that is not traditionally "local" (not usually my preference when I travel, but one must do what one must do), you definintely won't go hungry in Old San Juan. Here are some good non-vegetarian restaurants that really cater to vegetarians:
Tantra (the link will take you to the NYT review because the restaurant currently does not have a website), which offers Indian-Puerto Rican fusion cuisine in a semi-hip and romantic setting. The menu includes typical vegetarian Indian staples with a Latin twist.
|Tantra's vegetarian sampler includes vegetable curry, palak paneer, |
rajma, chana masala, masala dosai, sambar rice, naan, & papadams.
Cafe Berlin serves international cuisine, and its menu includes a separate vegetarian section with numerous options. The "veggie steak argentino" was both filling and delicious.
|Cafe Berlin's veggie steak argentino pan fried with sauteed onions, |
mushrooms, and red wine, served with garlic potatos and vegetables