Isla Foca was one of the most spectacular nature-related places we visited in Peru. How to get there:
1. Take the bus from Piura to Paita (1 hour, 4 soles one way, companies -- Dora or Hermanos Tume, can easily be found in Google maps).
2. From Paita take the bus to La Islilla (1 hour, 6 soles one way, the bus can be found at the end of the market place, ask the locals about the market).
3. In La Islilla take a boat to Isla Foca.
You could arrange a tour in advance, iPeru in city center of Piura will help you with the contact details).
You could also just go there and ask any available fisherman with the boat to bring you to the island, some of them could offer you the ride themselves. Price is negotiable, we agreed on 100 soles for 2 people (both ways, a trip around the island, the fisherman picked us up in 2 hours).
You should spend at least 2 hours on the island, don't hesitate to climb the hills, you will be rewarded with an amazing view of various birds, sea lions (from the top) and, if lucky, penguins.
4. It's better to visit the place in the morning. If it's too late to get back to Piura, you could find some cheap hotels in Paita.More