Aberdeen

Hakui, Japan
Kanazawa, Japan

Lynden

Langley, B.C., Canada

Anacortes

Lomonosov, Russia
Kisakata, Japan

Lynnwood

Choluteca, Honduras

Auburn

Kasuga, Japan *

Moses Lake

Yonezawa, Japan

Bellevue

Hualien, Taiwan
Yao, Japan
Kladno, Czech Republic
Liepaja, Latvia

Mount Vernon

Chilliwack, B.C., Canada
Kure, Japan

Bellingham

Nakhodka, Russia
Port Stevens, Australia
Tateyama, Japan
Punta Arenas, Chile
Bingen, Germany

Okanogan

Keremeos, B.C., Canada

Bremerton

Kure, Japan
Olongapo, Philippines

Olympia

Olympia, Greece
Samarkand, Uzbekistan
Yashiro, Japan *

Brewster

Takahagi, Japan

Omak

Summerland, B.C., Canada

Camas

Hosoe, Japan
Taki, Japan

Port Townsend

Jalapa, Nicaragua
Ichikawa, Japan *(pending)

Chehalis

Inasa, Japan

Pullman 

Kasai City, Japan *

Chelan

Tojo, Japan *

Puyallup

Kuima, Japan

Edmonds

Hekinan, Japan

Renton

Nishiwaki, Japan *

Everett

Iwakuni, Japan
Sovetskaya Gavan, Russia
Kligo, Ireland

Richland

Hsinchu, Taiwan

Federal Way

Hachinohe, Japan

Sequim

Yamasaki, Japan *

Ferndale

Miyoshi, Japan

Seattle

Beersheba, Israel
Bergen, Norway
Cebu, Philippines
Chongqing, China**
Christchurch, New  Zealand
Galway, Ireland
Gdynia, Poland
Haiphong, Vietnam
Kaohsiung, Taiwan
Kobe, Japan *
Limbe, Cameroon
Managua, Nicaragua
Mazatlan, Mexico
Mombasa, Kenya
Nantes, France
Pecs, Hungary
Perugia, Italy
Reykjavik, Iceland
Surabaya, Indonesia
Taejon, Korea
Tashkent, Uzbekistan

Friday Harbor

Terschelling, Netherlands

Shelton

Sanyi, Taiwan
Talsi, Latvia

Gig Harbor

Sakhalin Island, Russia

Spokane

Jilin City, China
Limerick, Ireland
Lubeck, Germany
Makhachkala,Georgia
Nishinomiya, Japan *

Issaquah

Sunndal, Norway

Tacoma

Aalesund, Norway
Davao, Philippines
Fuzhou, China
George, South Africa
Kiryat Motzkin, Israel
Kitakyushu, Japan
Kunsan, Korea
Vladivostok, Russia
Taichung Taiwan

Kelso

Kelso, Scotland
Sagara, Japan

Tukwila

Ikawa, Japan

Kennewick

Ying Ko City, Taiwan
Taoyuan City, Taiwan

Vancouver

Arequipa, Peru
Joyo, Japan

Kent

Castlereagh, Northern Ireland
Kaibara, Japan *
Kherson, Ukraine
Yangzhou, China

Walla Walla 

Sasayama, Japan *

Kirkland

Emmerich, Germany

Wenatchee

Kuroishi, Japan
Misawa, Japan
Tynda, Russia

Kittitas Co.

Sanda City, Japan * (county-city)

Yakima

Itayanagi, Japan
Derbent, Russia
Keelung, Taiwan

LaConner

Olga, Russia
San Rafael del Sur, Nicaragua

*     - in Hyogo Prefecture, Japan (sister state-1963)
**    - in Sichuan Province, China (sister state-1982)

Longview

Mandane City, Philippines