Pedro's of Kennebunk is one of our very favorite restaurants in the Kennebunk area and the best Mexican food for miles around. The location is actually in 'Lower Village' of Kennebunk, about 2 tenths of a mile from Dock Square, Kennebunkport. It is not a large restaurant, although outside seating when the weather is good basically doubles the number of tables. The food is GOOD, the prices are reasonable, and they sometimes have live entertainment. It has become very popular, so you can expect to wait a while to be seated and they do not take reservations (at least I do not think so). In the warmer months with tourists in the area it gets ridiculously busy and unless you show up early you should be prepared to wait for a while.
Parking is a little bit of a challenge, however, there is a large parking area around the corner that tourists have not discovered yet. :-) They have a fire pit outside that adds character and warmth and the decor is 'interesting' with all sorts of scavenged Mexican artifacts. It can be really loud indoors when it is full, which is most nights, so much so that having a conversation can be difficult. This is because of low ceilings and high density of patrons. The bar is small, but a good place to hang out as you wait for a table. Service has always been good, even when they are really busy. They have a large selection of Tequila if you are into that and a few aged rums, although the prices are a bit high. They also, predictably, have a large Margarita menu.
I highly recommend Pedro's as a place to try if you like Mexican food, are in the Kennebunk/Kennebunkport area, and are willing to go early or wait a while.