For many years, schools have visited the outdoor learning residential centre at East Barnby, near Whitby.
The trip has been subsided by North Yorkshire County Council, which reduced the cost considerably. However, the council says it is unable to subsidise the trips.
Jessica Warren, mum of Fred Humphries at Barrowcliff School, said they will not be “able to afford the huge rise in price” despite being a “working family”.
The mum-of-three said: “My son has been excited for a couple of years now to go into year four so he can go to East Barnby, as his older sibling has already been and Fred knew what it was like.
"There is not a chance that we can pay £350, and other parents have said the same.”
A spokesperson from North Yorkshire County Council said: “In the past North Yorkshire was able to hold back some Government school funding to support the outdoor learning service, particularly to enable free access for children on free school meals. This is no longer possible. All Government schools funding must now be passed on directly to schools.
“Last year the local authority provided transitional funding for one year to continue free access for children on free school meals.
"The council gave headteachers notice of the change so they could plan ahead and ring-fence money for outdoor education from their own pupil premium funding (£1,320 per child) for children on free school meals.
“This would ensure those pupils eligible for free school meals could still benefit from a high quality residential education trip to East Barnby or Bewerley Park, which provide proven benefits for children’s educational development and well-being.”
Barrowcliff School were contacted but were unavailable to comment.
In a letter, the school told parents about the lack of subsidy and asked them to return a slip indicating whether they would pay for the visit or not; the school’s booking would be cancelled if there was insufficient interest.