Mexico's Comision Nacional de Acuacultura y Pesca writes the rules for sport fishing in Mexico. Shore fishermen do not need a license, although if you're planning on going out another day on a boat, you do need one. You may have only one line in the water and you may not use an electric reel (those are limited to handicapped fishing fans). The limit is 10 fish per day, and five of a single species. For blue water fish like marlin and swordfish, the limit is one per day.
You are not likely to encounter marlin or tuna when you fish from the beach in Baja, California. Ocean whitefish and roosterfish are common. Perch and croakers are also a possibility.
Medium weight line and a medium spinning reel can help you land bigger fish. Lighter line may trick more fish, but the big guys are more likely to break away when you try to reel them in. Expect to pay for a high-end surf fishing rod. While it's not impossible to have some success with fly fishing gear, ocean waves can mess with your line, so spinning reels tend to be more effective in heavier surf.
Fish like to eat other fish, so live bait---small fish---is a good choice. You can also use big chunks of dead fish and squid. As for lures, the fish seem to hit on shiny, silver lures that spin through the water, perhaps because they resemble the little fish they're used to eating.
Many fish seem to be attracted to food, and thus to fishing lures, just after sunrise and right before sunset. You can fish from any beach or seashore that is open to the public. If you're staying in a resort or villa with a private beach, you can try that as well. If you're not having any luck where you're standing, walk down the beach until you run into fish.
There are several towns in Baja, California where shore fishing is a daily activity. They include Playas de Rosarita, Ensenada and San Felipe. Further south, California Sur, Cabo San Lucas, La Paz and Puerto San Carlos welcome shore fishing. You can reach most of them on the Transpeninsular Highway or Mex 1.
Stay away from turtles and marine mammals---it is never legal to take these, no matter where you are.
