Another great thing about Lisbon is that the beach is so close to the capital. In about 30 minutes by bus, you can bury your feet in the sand and swim in the Atlantic Ocean.
The beaches on the left side of the village are more spacious, so take a walk on the beach to get to those ones and relax. Each beach has a different name and most of them have a bar where you can eat sandwiches, salads or snails and have a drink.
You might meet with some fishermen and if you see some people with the bottom-up, they are catching conquilhas.