We shall have to imagine what Hungarian guys were on the beach but you seem to have picked up on the water polo club Debrecini Civis Polo Vizilabda S E, from Debrecen.
Club sponsors appear to include Arena and, surprisingly, French supermarket chain Auchan. You have probably found the best pic (which coincidentally includes yet another mysterious orange speedo) but there is also a photo gallery on their website
http://www.dvse.hu