Travelling from UK to Ireland via the ferry, your horses only need their I.D.document- (passport)
At present shipping to France, horses entered in FEI competition, (plus Thoroughbreds), along with their passports need to have a certificate called a DOCOM, provided by an approved shipper. This certificate lasts for 10 days and means that these 'high health status' horses are exempt from needing health papers signed by a vet. They are granted 'high health status' because of their compliance with vaccination requirements and FEI regulations.
All horses other than FEI horses require a health certificate and an export licence.
At HTS we intend to remain as informed and Brexit - prepared as possible, regarding the movement of all horses.