Young children can travel free to and from Heathrow on several services, but the rules differ depending on which one you use. On Heathrow Express, children aged 15 and under travel free when accompanied by a paying adult. On Transport for London services, which cover the Elizabeth line and Piccadilly line into Heathrow, children under 5 travel free with a fare-paying adult, and children aged 5 to 10 travel free with the right ticket or card. Here's how each service actually works.
Heathrow Express: free for under-16s
Heathrow Express states that children aged 15 and under travel free on its trains when accompanied by a paying adult. Trains are step-free with room for luggage and buggies, and the journey between Heathrow and London Paddington takes around 15 minutes. There is no need to buy a separate child ticket; the free travel applies automatically at the gates when travelling with an adult ticket holder.
Elizabeth line and Piccadilly line: TfL's child fare rules
The Elizabeth line and Piccadilly line into Heathrow are part of the Transport for London network, so standard TfL child fare rules apply rather than a Heathrow-specific policy:
- Under 5s travel free with a fare-paying adult on TfL services, which includes the Elizabeth line and Piccadilly line sections serving Heathrow.
- Ages 5 to 10 travel free on TfL services, subject to checking current eligibility and having the right ticket or card for the child.
- Ages 11 to 15 are not automatically free. They need an 11-15 Zip Oyster photocard to get free travel on buses and trams and discounts elsewhere on the network; without one, a child fare or adult fare may apply depending on the ticket type used.
Because Heathrow's Elizabeth line and Piccadilly line stations sit within a special airport fare zone, always check the current child fare or free-travel eligibility for the specific Heathrow leg before you travel, using TfL's official fare checker, since airport-zone pricing can work differently from a standard zone 1-6 journey.
Practical differences between the two networks
| Service | Free child age | Condition |
|---|---|---|
| Heathrow Express | 15 and under | Travelling with a paying adult |
| Elizabeth line / Piccadilly line (TfL) | Under 5 | Travelling with a fare-paying adult |
| Elizabeth line / Piccadilly line (TfL) | 5-10 | Eligible with the correct ticket or card |
| Elizabeth line / Piccadilly line (TfL) | 11-15 | Needs an 11-15 Zip Oyster photocard for discounts; not automatically free |
Which is the better value option for families
If you have children aged 11 to 15 and no Zip Oyster photocard, Heathrow Express's blanket free-travel-under-16 rule can work out considerably cheaper for that age group specifically, even though the standard adult fare on Heathrow Express is higher than the Elizabeth line. Do the sums for your specific family: a large group with several older children may save more overall on Heathrow Express than paying full child or adult TfL fares for the same ages.
For families with only under-5s, or with a Zip Oyster photocard already sorted for older children, the Elizabeth line and Piccadilly line are typically the cheaper way to reach Heathrow from central London, and run more frequently across the day.
How to arrange a Zip Oyster photocard before you travel
If your children are 11 or older and you plan to use TfL services more than once, apply for an 11-15 Zip Oyster photocard in advance through Transport for London. This card unlocks free travel on buses and trams and discounted travel elsewhere on the network, and needs a passport-style photo and processing time, so it is not something to arrange on the day you fly.
Practical tips
- Have proof of age ready. Staff can ask to see it, particularly for children who look close to a fare threshold.
- If travelling with a mixed-age group, work out both options (Heathrow Express vs Elizabeth line/Tube) before you buy tickets, since the cheaper choice depends on exactly how many children fall into which age band.
- Check TfL's official fare finder for the Heathrow-specific leg before you travel, since airport-zone pricing is sometimes different from standard London fares.
Checked 2026 against Heathrow Express's official family travel policy and Transport for London's free and discounted travel guidance.