A nine-strong team of senior inspectors will next week begin the mammoth task of sifting through the forms to decide which should be inspected as a priority.
With an estimated 3,000 to 5,000 outdoor adventure centres throughout the UK offering activities from pot-holing, pony-trekking, climbing and canoeing, they will have their work cut out.
Safety standards at outdoor centres are being tightened following the Lyme Bay tragedy three years ago when four teenagers died on a canoeing trip.
And the deadline for centres to register for a licence comes just a month after a 13-year-old boy died on a school trip to a North Yorkshire beauty spot. Richard Barber, one of 30 children from Ladderbanks middle school, Baildon, West Yorkshire staying at an outdoor education centre owned by Bradford Council, was found in a waterfall pool.
Under the Activity Centres (Young Persons Safety) Act, commercially-run enterprises had until yesterday to register with the Government-appointed independent inspection agency, Tourism Quality Services.
Local authority-owned centres like Buckden House in the Yorkshire Dales where the Ladderbanks middle pupils were staying will also be subject to inspection under the legislation.
Outdoor activity centres will have to meet standards for equipment, qualifications for instructors and safety management and a code of practice will state what levels of skills are needed to cope with different hazards.
The Act, introduced via a private member's Bill from Labour MP David Jamieson, covers 26 activities in the categories of climbing, water sports, caving and trekking.
And Tourism Quality Services (TQS), which has been approved by the Health and Safety Commission as regulator for the industry, has until the end of September 1997 to inspect all centres who applied for a licence.
Activity centres run by voluntary bodies such as the scouts do not have to be licensed. Nor do those offering activities such as archery, motor sports or shooting.
There is no central database of outdoor activity centres but TQS, which administered the Wales Tourist Board's voluntary accreditation scheme, estimates it has at least 2,000 applications to deal with. Many will be multiple applications from local authorities who own several outdoor centres.
Several companies have been more than keen to register - and have even been prepared to change the activities they offer - in the belief that the licence will give them a commercial edge.
At least 600 people have applied to TQS for inspection work and John Walsh-Heron, its managing director, insisted standards for the centres in the Cairngorms would be identical to those in Cumbria and Dartmoor.
"These regulations are being applied to reassure parents and schools and those who send young people on these kind of activities that there are proper safety management systems in place. We don't want to stop young people from experiencing exciting activities. We want them to be able to do so without risk of death or injury."