Alphabetically Union List - I
- IDS Labour Union
- Imax Labour Union of Thailand
- Imperial Labour Union
- Imperial Thai Supervisory Labour Union
- Inca Labour Union
- Indo Thai Labour Union
- Indo-Rama Chemicals Labour Union
- Industrial Estate Authority of Thailand Labour Union
- Industries Garment Relation Labour Union(IQRU)
- Infus Medical Products Labour Union
- Inter Navanakhon Labour Union
- Interfern Navakhon Labour Union
- Intermoda Labour Union
- Internaitonal Rubber Parts Labour Union
- International Footware Labour Union
- International Oceanliners Workers Union
- International School Workers Union
- Interseat Connection Labour Union
- Invented Token Labour Union
- Ion Made Labour Union
- IP Manufacturing Labour Union
- IRC Tire & Rubber Manufacturer Labour Union
- Iron and Metal Enterprise Employees Union
- Iron and Metal Labour Union of Thailand
- Iron Pipe Labour Union
- Iron Pump and Metal Workers Union of Thailand
- Iron Sheet Labour Union
- Isan Sag Workers Union
- ISLAM Banking of Thailand Trade Union
- Islamic Bank Workers Union of Thailand
- Isuzu Auto Engine and Parts Workers Union of Thailand
- Isuzu Fishing Tackle (Thaialnd) Labour Union
- ITE Labour Union
- ITF Workers Union
- Ito Thailand Labour Union
- ITV Labour Union
