Umi No Ichi is the sightseeing hub of  Kesennuma. It is a two-story complex located next to Kesennuma Fish Market and Kesennuma Port. On the first floor, vendors sell fresh catches of octopus, hoya (sea pineapple), and other seasonal fish. Adjacent shops sell seafood products, notably shark fin and red crab, and all sorts of local souvenirs. There are also several seafood restaurants serving fresh local cuisine.

On the sightseeing side of things, is home to the quirky Ice Aquarium, and Japan's only shark museum. It is also home to a shop (and shrine!) dedicated to Hoya Boya, the mascot of Kesennuma who brandishes a fish sword. The Kesennuma Tourism and Convention Bureau is located on the second floor of Umi no Ichi as well. They offer English assistance, coupons, organized tours, and bicycle rental.