Honolulu, Oahu is a fantastic destination for couples in their 20s seeking a mix of relaxation and excitement. You can enjoy world-class surfing on famous beaches like Waikiki, explore vibrant local food scenes, and hike scenic trails such as Diamond Head. The city also offers great snorkeling spots and cultural experiences, making it a perfect single spot for your interests without the need to island hop.

Maui is a fantastic choice for a couple in their 20s looking for a mix of relaxation and excitement. You can enjoy world-class surfing spots, breathtaking hikes like the trails in Haleakalā National Park, and snorkeling in crystal-clear waters at Molokini Crater. The island also offers a vibrant food scene with local Hawaiian cuisine and fresh seafood to explore.