Kotychi (Greek: Κοτύχι) is a lagoon in the northwestern part of the prefecture of Ilia, Greece. It straddles the municipal boundaries of Lechaina and Vouprasia. It is located 61 km SW of Patras, 48 km NW of Pyrgos and about 22 km from Kyllini. The lagoon is connected with the Ionian Sea. It is a protected wetland area. The area has birds and Kotychi is one of the most important areas for birds in Greece. It is home to crayfish species. Its surface area is 3.7 km².