How to swim in the water with your period?

Hi, just before I went to my beach trip to Marbella, my period came. I have to say my period is not heavy, but more light-medium. I don�t have a very big vaginal opening. I will spend mostly all day and every day for a week on the beach, so I will have a few days without my period, about 3. I�ve already tried tampons, and I have to buy some, but is there any other way? Also, any tips to not... You know...?