The borough is reporting above national rates of unauthorised holiday in both primary and secondary schools.
Penalties for term time leave have rose by 50% between 2022 and 23 and last year as well.
Prices for flights and holidays can be up to 50% cheaper during term time.
But school heads say even missing one week can result in gaps in knowledge and children falling behind their friends.
One situation relayed to Jackie News is of a child who was the youngest in their year and was taken out of school for 4 months.
In Hounslow, during the first two weeks of the 2024 Autumn term, 263 primary phase pupils of compulsory school age were absent for at least one day due to unauthorised holiday.
The total number of days missed, for this reason, was 1,025 with pupils missing an average of 3.8 days.
Across the secondary phase, 141 pupils were absent for this reason with the total number of days being 532 and the average being 3.7 days.
Cabinet Member for Education, Children, Skills, and Employment, Councillor Samia Chaudhary also urged parents to consider the consequences of term time leave: “We know there is a clear link between absence and attainment, so we’d urge parents to think very carefully about taking holidays during term time. While we are sympathetic to some of the reasons involving families, there remains an increase in parents simply taking children out of school for cheaper holidays. We must put the education of our children first and we will fine consistently irresponsible parents.”