The Transit Go app can be used for bus, Link light rail, ferry, water tax, street car, and Sounder rail fares. Transit GO can only be used to purchase tickets or single-service day passes; it does not provide transfers and cannot be used on the monorail
Be sure to activate your tickets on Transit Go before boarding or entering the platform; tickets you have purchased are not valid for travel until activated
On buses, ferries, and the water taxi be prepared to show your ticket (phone screen) when boarding. On other services be prepared to show your ticket if requested by a fare enforcement agent