That sounds like a great idea! Nha Trang is a beautiful coastal city in Vietnam with plenty of things to see and do. Here are some activities that you might enjoy during your summer vacation in Nha Trang:

Visit the beaches: Nha Trang is famous for its stunning beaches, such as Tran Phu Beach, Hon Chong Beach, and Bai Dai Beach. You can spend your days lounging on the sand, swimming in the clear blue water, or trying out water sports like surfing, snorkeling, or scuba diving.
Explore the islands: Nha Trang is surrounded by a cluster of islands, such as Hon Tre Island, Hon Mun Island, and Hon Tam Island. You can take a boat tour to visit these islands, and enjoy the pristine beaches, coral reefs, and marine life.
Discover the local cuisine: Nha Trang is known for its fresh seafood, and you can sample a wide range of dishes such as grilled squid, steamed crab, and seafood hotpot. You can also try traditional Vietnamese dishes like pho, banh mi, and fresh spring rolls.
Visit cultural attractions: Nha Trang has several cultural attractions worth visiting, such as the Po Nagar Cham Towers, Long Son Pagoda, and the National Oceanographic Museum of Vietnam.
Relax at hot springs: Nha Trang has several hot springs where you can soak in mineral-rich water and enjoy the tranquil scenery.
Overall, Nha Trang is a great destination for a summer vacation, offering a mix of beaches, culture, and delicious food.