We will stopping in Majorca for a single day in March. Any suggestions on what to see or do would be appreciated..
Do you know which part- will it be Palma? If it's in Palma there is loads to do there- the cathedral is beautiful and you can enjoy walking thru the old town, plaza mayor, Santa Catalina Market, etc.
With only one day I would suggest sticking to Palma. There's plenty to see and do that would occupy a single day. I can't count how many times I've been there but suffice to say it's my favourite Spanish city.
Well, if you are only there for one day, I am assuming you may be on a cruise.
Therefore, your time will be limited by the ship arrival and departure. I am sure the cruise line has a number of organized tours you can purchase.
Also, March is too cold for swimming, although you could possibly take a little boat tour. However, the tourist numbers should be lower at this time. Mallorca has been getting slammed by tourism, and some of the citizens have protested.
I agree that Palma is a wonderful city to visit--the views are spectacular, the cathedral is magnificent, Bellver castle is nearby, and you can always shop for Majorica pearls.
If you want to go farther afield, highly recommended places to visit include Sóller, Valldemosa, the Drach Caves, and the Cap de Formentor.
Here is a resource from Spain:
https://www.mallorca.es/en/things-to-do-and-see
Have a great visit!