House Bill 2638 now moves forward to the Senate Ways and Means Committee for further debate and, if passed, will allow in-person and on-premises mobile sports betting at 29 tribal casinos within the state.
Players would be able to place bets on professional and college sports, international competitions and esports events.
Wagers will only be accepted while players are physically at the tribal casino.
The bill also states that, upon request of Indian tribes, each class III gaming compact may be amended to authorise sports betting, providing it includes licensing fees and details on how it will be operated and regulated.
Should the bill pass, The Washington State Gambling Commission would be responsible for regulation and awarding relevant licenses to operators.
Last week, the bill passed through The Washington House of Representatives, by a vote of 83-14.
Currently, all gambling on the internet is illegal in the state, while the only type of sports betting that is legal relates to sports pools.