Weherahena Temple is one of the more memorable Buddhist sites near Matara, known for its large seated Buddha and painted tunnel-like interior spaces. It is colorful, devotional, and a little theatrical, which makes it stand apart from quieter coastal temples.
The temple is easy to combine with Matara's forts, beaches, and other religious sites. Dress respectfully and give yourself time to look at the murals rather than treating the big Buddha as the only point of the visit.