Cinque Terre

Monterosso has the bigger, main beaches (the more traditional beaches.) Vernazza has a quasi beach and Manarola has an area where many of the locals swim off of the rocks. The towns do get storms that roll in during the winter so I'm not sure how safe Vernazza or Manarola are to swim. I would guess (though I cannot say for sure) that your best bet would be Monterosso as they have true beaches with calmer surf.

Thank you so much for your reply and suggestion about beaches being safer in Monterosso as they may be calmer in winter. Do you know if anyone goes for a quick dip mid Feb through to Mid March?

I would also check the tide schedule a few days in advance . The difference between high and low tides, especially in the winter, can be significant. Winter storms can bring tide surges . I wish you a safe swim.

Thank you! Any recommendations for a BnB where we can cook breakfast and do laundry from mid Feb to mid March in Monterosso?

Do you know if anyone goes for a quick dip mid Feb through to Mid March?

I imagine it would be 'quick', much like the 'polar plunge' events that happen in the US on New Year day.

Monterosso is definitely the place with a beach that would permit you "to run into the ocean quickly",

You might do some google searches on swimming in that time frame - I just did one and most results said swimming in CT is from "May to September." That could be due to access to facilities (there are private beaches with chair rentals in some places) though I suspect it is squarely due to the very cold temperatures. One quote:

The weather is not very hot yet, so March to May is considered the
best period for walking the trails. It is still too early to swim,
even though you can see some brave people on the beaches from mid-May,
already taking a dip in the cool Ligurian waters.

This website lists the water temperature in Monterosso in February - I might dip my toes in but definitely not swimming temps (I live in Pacific NW, we do not swim in the ocean even in summer) https://www.seatemperature.org/europe/italy/monterosso-al-mare-february.htm

We stayed at Villa Steno in Monterosso 2 years ago. Absolutely fabulous. Breakfast included. They took care of our laundry for a very reasonable price. We had a wonderful 5 nights visiting Cinque Terre.

We stayed in Monterosso for three nights the first week of November 2023. Many if not all of the blue trails were closed due to weather encountered at the end of October. The upper trails and the one to Levanto were open, as I recall.

It was sprinkling when we arrived and it turned into a torrential downpour by the time we ventured out to find dinner, with extremely high wind.

There was violent surf for the next two days - water was splashing up onto the promenade along the beach. The seas were too rough for any boats to be in the water. They were doing remedial work on the beaches, which are the most expansive in the CT. Got some great pix of water splashing up against the rocks.

The general point is that there's no way to predict winter weather in advance. It may be fine for hiking and chilly swimming while you're there, but have a plan B to visit other towns along the rail line, or bring a good book, just in case...

Monterosso's beach is probably your best bet but Vernazza does have a wee sandy one near the piazza that might work. I can't imagine anyone swims during the winter months but never say never.

https://www.cinqueterre.eu.com/en/cinque-terre-beaches

Do make note of markcw's caution about the possibility of trails being closed to weather or repair in winter? If you haven't found it yet, the park's website is where you want to check for conditions, warnings and closures. Trails in black on the map means they're closed; click on any line on the map for individual trail number and more info under "View the itinerary".

https://www.parconazionale5terre.it/Eindex.php
https://www.parconazionale5terre.it/Esentieri-outdoor.php