Uni Sushi | What Is Uni? Types, Seasons, and 5 Recommended Sushi Restaurants in Tokyo

What Is Uni?

Uni: A Close Relative of Starfish

Uni is a type of echinoderm that lives in the ocean, known for its round, spiny shell. It belongs to the same family as starfish. The part we eat is the sea urchin’s immature gonads-either the testes or ovaries—which are nearly identical in both appearance and taste, making them difficult to distinguish.

Uni has been a culinary staple in Japan, Korea, and parts of Europe for centuries. In the United States, however, it was not traditionally popular. But with the rise of Japanese cuisine worldwide, more people in the U.S. have developed a taste for uni in recent years.

Types of Uni

There are over 800 species of sea urchins worldwide, but only about six are commonly eaten in Japan:

Murasaki Uni (Purple Sea Urchin)

Known for its yellowish roe and rich, intense flavor.

Kita-Murasaki Uni (Northern Purple Sea Urchin)

Has a mild, slightly sweet taste, making it a popular choice for sushi.

Bafun Uni (Horse Dung Sea Urchin)

Small but packed with a strong umami flavor, often used in processed uni products.

Ezo-Bafun Uni (Hokkaido Horse Dung Sea Urchin)

Features bright orange roe with a sweet, concentrated taste.

Aka Uni (Red Sea Urchin)

Extremely rare and often called the “phantom uni.” Highly prized for its strong sweetness and exceptional flavor.

Shirahige Uni (White Beard Sea Urchin)

Native to Okinawa and southern Japan, it has a light, refreshing taste but is not commonly eaten.

Taste And Texture

Sea urchin is characterized by its rich, creamy, and distinctive texture that melts in your mouth. It has a unique umami flavor that combines butter-like sweetness with saltiness. Another characteristic is what's called the "rocky shore aroma" - the scent of the sea. Lower quality sea urchin has a bitter taste, but high-grade sea urchin is sweet, rich, and has a pleasant aroma.

How to Identify Delicious Uni

There are two main ways to identify delicious sea urchin (uni). The first is judging by appearance - color, shape, and luster. While color varies among individual sea urchins, those with a glossy appearance and intact shape are considered delicious. You must be careful with sea urchin that has poor freshness, as the flesh dissolves, loses its luster, and develops an odor. The second factor is whether additives are used. Since it's difficult to distribute sea urchin while maintaining the shape of the flesh, additives are often used in many cases to improve preservation. While these are harmless to the body, using additives makes the sea urchin taste slightly bitter. Choosing products labeled as "salt water uni" or "alum-free" allows you to better enjoy the natural flavor of sea urchin.

The Season for Uni

The season for uni varies by species, but generally, it runs from June to August. During this time, the reproductive organs of the uni mature, bringing out its best flavor.

Famous Uni-Producing Regions in Japan

In Japan, uni from Hokkaido is particularly renowned. The main types of uni harvested there are Kitamurasaki Uni and Ezo Bafun Uni, with Kitamurasaki Uni being especially popular as a sushi topping. Hokkaido uni thrives in cold waters and feeds on abundant kelp, which results in firm flesh and a rich, flavorful taste.

Where to Eat Uni in Japan

Uni is considered a luxury food in Japan, so it's not something people typically eat every day. At high-end sushi restaurants, you can savor fresh, top-quality Japanese uni. However, you can also find uni at conveyor-belt sushi or more casual sushi spots. The ability to offer premium uni at lower prices is due to advancements in technology and business efforts. Uni that doesn't use myouban (calcined alum) lets you experience its pure, natural flavor, though it can be challenging to preserve. Since it’s usually served at upscale restaurants, if you want to enjoy the true taste of uni, it’s best to visit a high-end sushi spot.

Drinks that Go Well with Uni

Dry alcoholic beverages pair well with the sweetness and umami of sea urchin. Dry white wines and champagne are certainly recommended, but the top recommendation is to drink it with dry Japanese sake. Most sushi restaurants have Japanese sake available, so I hope you'll enjoy sea urchin together with dry Japanese sake.

Dishes that Use Uni

Sea urchin is primarily eaten raw as sushi or sashimi. It's also sometimes used for its vibrant yellow color as a garnish, and at high-end restaurants, it's used in meat dishes as well. Additionally, it's used in non-Japanese cuisine such as pasta and sea urchin sauces. Italy in particular has a long-standing culture of eating sea urchin, and there are many Italian dishes that incorporate sea urchin.

Uni Sushi

Uni sushi is typically served as gunkan-maki (battleship roll). This style was created by the chefs at Ginza Kyubey, one of Japan’s most famous sushi restaurants. It consists of vinegared rice wrapped in seaweed, topped with uni. However, some sushi chefs feel that the seaweed can overpower the uni's delicate flavor, so they may serve it as sushi instead.

For the best uni experience in Japan, it's recommended to visit a high-end sushi restaurant.

Where to Find Delicious Uni at Sushi Restaurants in Tokyo

Udatsu Sushi （宇田津 鮨）

Selected Restaurant

Michelin Guide, 2026

This sushi restaurant, built around the concept of "Art x Sushi," is extremely popular with foreigners. The atmosphere is calm and refined, and the dishes are true works of art. The uni sushi here features both bafun uni and murasaki uni, served lavishly with a special seaweed accent carefully chosen by the chef. It's a visually stunning and flavorful dish that delivers the best of both worlds.

Sushi Kakizaki （すし柿崎）

Located in Ningyocho, this hidden gem is run by a husband-and-wife team. The chef, who has worked in the sushi departments of luxury hotels, prepares a course of appetizers and sushi using seafood directly sourced from the Toyosu market. Despite its price, the course offers a wide variety of dishes and delivers great satisfaction. A standout experience is the signature uni tasting, where you can compare bafun uni and murasaki uni—a truly luxurious experience.

Sushi Rizaki nishiazabu （鮨利﨑 西麻布）

Using the finest ingredients carefully selected by wholesalers for our restaurant - including tuna, sea urchin, abalone, silver-skinned fish, shrimp, and crab - we offer not only appetizers and sushi that draw on our experience in Japanese cuisine, but also incorporate dashi made from the day's fresh fish into our dishes, devising ways for customers to enjoy the authentic flavors of the ingredients themselves.

Sushi Nagashima （鮨 長島）

The course content features appetizers and sushi served alternately. Our tuna is sourced from "Yama-kou," a purveyor to renowned establishments, while our sea urchin comes from various regions depending on the season, including Kyushu and Hokkaido. Additionally, we prepare spiny lobster from Mie and Chiba prefectures as nigiri sushi.

Sushi Kitamura （鮨きたむら）

We are particular about sourcing each ingredient individually. Our tuna comes from a renowned tuna wholesale specialist in Tsukiji. Additionally, we gather seasonal ingredients from all across Japan through direct shipping from their places of origin - red sea urchin, bigfin reef squid, and tilefish from Fukuoka, purple sea urchin and barfin flounder from Hakodate, among others.