They confirmed there is space for three more teams to take their places on the start line in the French city of Reims on 5 July.
The route will cover six countries, including Switzerland and Germany, in three days. So far, 21 teams have entered the challenge, which features Not Just Travel and Holiday Extras as headline sponsors.
The event, co-founded and run by Beachcomber Tours sales director Sarah Archer, will conclude in a secret location on 7 July.
Organisers hope to raise a minimum of £40,000 for charity, taking the fundraising total above the £200,000 mark.
Last held in July 2019, the Travel Trade Crusade has so far raised £165,000 across the previous four rallies.
