IMO numbers are issued by IHS Markit on behalf of the IMO 

Contact IHS Maritime & Trade

IHS Markit
Sentinel House
163 Brighton Road
Coulsdon, Surrey
CR5 2YH
United Kingdom

Customer Services & Technical Support
Tel: +44 (0) 1344 328300
customer.support@ihs.com
Contact the IMO
Tel: +44 (0) 20 7735 7611
info@imo.org
Ship IMO Department
Hours: 8am - 5pm GMT
Tel: +44 (0) 1344 328300
ship.imo@ihs.com
Owners & Managers Department
Hours: 8am - 5pm GMT
Tel: +44 (0) 1344 328300
maritime.owners@ihs.com