Meeting acquaintances while on a boat on the sea

So my mother and I were visiting Spain in my summer holidays to meet up with my grandpa who was currently on a sailing trip there. So we stayed on his boat for about a week and one evening we were sailing into a small bay and anchored to spend the night there. My mum and I were bored so we put the small rubber boat into the water and paddled around a bit. Eventually we saw two kids and their father in a rowboat a few meters away from us. As we got closer we realised that we knew them because the kids visited the same kindergarden and elemantary school as me. When they also recognized us we met to talk a bit. We all could not believe this had happened. They told us tehy were staying in a hotel in the bay and they hired the boat just for an hour. That's how we randomly met acquaintances somewhere on the sea in Spain.