I assume you are asking about claiming expenses for the child and dependent care credit. If you pay in an earlier year you claim the expenses in the year that the care is provided. If you paid part of the cost of 2025 summer camp in 2024, you include it in the expenses that you report on your 2025 tax return. If you paid part of the cost of 2024 summer camp in 2023, you include it in the expenses that you report on your 2024 tax return.
You probably know, but just as a reminder, only day camp qualifies for the child and dependent care credit, not overnight camp.
