Entry and exit are ridiculously easy. Gear up on the concrete platform next to the boat ramp and then hop into 4' of water off the end. The bay is relatively shallow but there is lots to see. There is a wrecked shrimp trawler right in front of the entry, swim about 70 yards out and it is just past the line of rocks that break the surface. At low tide the hull of the boat protrudes from the water, the wreck sits in about 15'-20' of water. If there isn't too much surge you can penetrate the wreck, the interior has a lot of encrusting corals, so please be careful! To the right of the boat ramp is what is referred to locally as the "Spanish anchor", supposedly off a Spanish Galleon. It is a huge "anchor-shaped" anchor, obviously quite old, so... There is a lot of life to see, look for the huge eels in the sand-flats or scorpion fish among the rocks. Spotted stingrays are very common. During my last trip there I videoed 5 different species of puffers, including a two-foot monster inside the wreck. The shallow depths (max. depth I have found is around 35') make this a great place to snorkel. You can enter from the boat ramp, but if you are just snorkeling you can enter anywhere along the beach as well. This place is very special, if you go you will want to spend the day. Going to Tehuamixtle is like stepping back 20 years. The beach is always deserted, the water is warm and blue, and there are no beach vendors selling Indonesian sarongs.
Drive South from Puerto Vallarta on Highway 200 for about 40 minutes to the town of el Tuito (look for the Pemex station on the left). Take a right into the town. When you get to the main square keep to the left, you will see a Tehuamixtle sign pointing to the left about a block past the plaza. If you have any doubt, just ask anyone how to get to Tehua (Tay-wah). After leaving town it is a scenic 45 minute drive over graded dirt roads. The trip used to require a high-clearance vehicle, but these days any rental car will get you there. Once you get to the Port of Tehuamixtle you can park on the main pier or next to one of the two restaurants in town. I like the restaurant "Liz Adriana" on the left.