The Sims 3/Ocean swimming

Ocean swimming is a feature that enables Sims to swim in the ocean or open seas, firstly introduced in The Sims 2: Bon Voyage for The Sims 2. It was later introduced for The Sims 3 in The Sims 3: Seasons, although the feature is now available in Patch 42 for players who do not have Seasons.

The Sims 2: Bon Voyage
Swimming in the ocean was first introduced in Bon Voyage. In the vacation destination of Twikkii Island, some lots are placed right on the shoreline, and Sims are able to swim in the ocean. Swimming in the ocean gives Sims a special positive memory.

Creating a lot that allows Sims to swim in in the beach requires players to open the Lots and Houses bin from the neighborhood screen and select Speciality Lots. There is then the option to Create a Beach via the button in the top-left corner, next to the thumbnails of speciality lots.

List of lots that contain a beach
All of the following lots are located in Twikkii Island.
 * Seawater Beach Paradise (Community lot)
 * South End Beach (Community lot)
 * Twikkii Beach Boardwalk (Community lot)
 * Brickstone Chateau (Residential lot)
 * Potterhouse Bungalows (Hotel)
 * Twikkii Beach Hotel (Hotel)

The Sims 3: Seasons
The feature was introduced for The Sims 3 with the announcement of Seasons. A few months later, the developers had confirmed that it would be on Patch 42, just for the players without Seasons.

Sims can swim in oceans near beaches and coastal areas at any time year-round. They can also swim in any body of water (e.g.: lake, river) that is not made in a lot, (e.g. if the player places a lot in the body of water, Sims can actually swim in it) whether commercial or residential. They can swim under bridges too. It can be done on any neighborhood, including World Adventures, store and custom neighborhoods.

Sims are able to swim on a body of water even if it has unroutable paint laid down beneath the water. There's a different paint type that's used around the edges of the world to block the camera from going too far – Sims won't be able to swim beyond that point (or wherever that paint is laid down).

When swimming, Sims gain their Athletic skill but lose energy motive, which can cause fatigue. They cannot drown or skinny dip. They can splash at one another, similar in a swimming pool, and also relax in the ocean on a lounger.

Sims can swim on oceans during the winter season and when swimming, they get a positive "Polar Bear Club" moodlet.

Pets cannot swim in any bodies of water.