| US Communities - WTA Purchasing Agreement | US Communities | Interlocal Agreement |
| WA_DES - WTA Purchasing Agreement | WA State Dept of Enterprise Services | Interlocal Agreement |
| WSDOT - WTA Emergency Response Mutual Aid | WA State Dept of Transportation | Interlocal Agreement |
| WSTIP - WTA Insurance Pool Membership | WA State Transit Insurance Pool | Interlocal Agreement |
| WSTIP - WTA Envision Driver Record Monitoring | WA State Transit Insurance Pool | Interlocal Agreement |
| WSTIP - WTA Emergency Response Mutual Aid | WA State Transit Insurance Pool | Interlocal Agreement |
| WWU - WTA 2017-2020 Student Pass Agreement | Western Washington University (WWU) | Interlocal Agreement |
| WCC - WTA Student Pass Agreement | Whatcom Community College (WCC) | Interlocal Agreement |
| WCOG - WTA Transportation Improvement Program | Whatcom Council of Governments (WCOG) | Interlocal Agreement |
| WCOG - WTA Metropolitan Transportation Planning | Whatcom Council of Governments (WCOG) | Interlocal Agreement |
| WCOG - WTA 2017 Smart Trips | Whatcom Council of Governments (WCOG) | Interlocal Agreement |
| WCOG - WTA MTP Matching Funds | Whatcom Council of Governments (WCOG) | Interlocal Agreement |
| WC Sheriff - WTA Work Crew Agreement | Whatcom County Sheriff's Office | Interlocal Agreement |
| COB - WTA Fiber Use Agreement | City of Bellingham | Interlocal Agreement |
| COB - WTA Communication System Use Agreement 2004 | City of Bellingham | Interlocal Agreement |
| COB - WTA Exectued Employer Bulk Pass 2010 | City of Bellingham | Interlocal Agreement |
| COB - WTA Extension of Sewer Service | City of Bellingham | Interlocal Agreement |
| COB - WTA Use of Right Of Way (BTS) | City of Bellingham | Interlocal Agreement |
| COB - WTA Signal Preemption | City of Bellingham | Interlocal Agreement |
| AWC - WTA Interlocal Health Care 2013 | Association of Washington Cities | Interlocal Agreement |
| COB - WTA Police Services | City of Bellingham | Interlocal Agreement |
| COB - WTA Maplewood Avenue Improvements | City of Bellingham | Interlocal Agreement |
| COB - WTA - WWU Lincoln Street Improvement Study | City of Bellingham & WWU | Interlocal Agreement |
| COE - WTA Purchasing Agreement | City of Everett | Interlocal Agreement |
| COS - WTA Purchasing Agreement | City of Seattle | Interlocal Agreement |
| Community Transit - WTA Purchasing Agreement | Community Transit | Interlocal Agreement |
| King County - WTA Purchasing Agreement | King County | Interlocal Agreement |
| KCDA - WTA Purchasing Agreement | King County Directors Association | Interlocal Agreement |
| Lummi Tribe - WTA Use of PTBA | Lummi Nation Transit | Interlocal Agreement |
| MRSC - WTA Small Works Roster Access | Municipal Research & Services Center (MRSC) | Interlocal Agreement |
| Ben Franklin Transit - Cooperative Purchasing Agreement | Ben Franklin Transit | Interlocal Agreement |
| Pierce Transit - WTA Purchasing Agreement | Pierce Transit | Interlocal Agreement |
| Skagit - WTA 80X Fare Revenue | Skagit Transit | Interlocal Agreement |
| Skagit - WTA Facilities Use and Hold Harmless | Skagit Transit | Interlocal Agreement |
| Spokane Transit - WTA Purchasing Agreement | Spokane Transit Authority | Interlocal Agreement |
| TCPN - WTA Purchasing Agreement | The Cooperative Purchasing Network (TCPN) | Interlocal Agreement |
| WC Public Works - WTA Pictometry | Whatcom County Public Works | Interlocal Agreement |