Today is National Flip Flop Day, which means that you’ll be able to get free Tropical Smoothie Cafe smoothies when you show up to a store location on this day.

The promotion runs from 2 p.m. to 7 p.m. on June 15 as you can get a free 16-ounce Sunshine Smoothie if you wear flip flops to any of its locations around the U.S. Flip flops are the unofficial sign of summer as they are comfortable and essential parts of your beach attire and it appears as if everyone around the country is finally ready to embrace the warm season.

The free Tropical Smoothie offer will net you a smoothie that combines orange, banana, pineapple and mango, some of the tastiest tropical fruits out there. The free smoothie is part of an initiative from the restaurant to raise money for Camp Sunshine, a year-round camp for kids with life-threatening illnesses for them and their families.

Although it is not necessary, customers are encouraged by Tropical Smoothie Cafe to make a contribution on Friday to help these children enjoy and live their lives to the fullest while you enjoy a delicious smoothie ahead of the first day of summer. The official beginning of summer will take place next week so make sure you prepare for that too.

Happy National Flip Flop Day!