For UK Junior ISAs in 2026/27: Vanguard JISA (0.15% capped £375) is the cheapest mainstream choice for long-horizon investing. AJ Bell JISA (0.25% capped) is the best balance of cost and product range. Below £5,000, InvestEngine and Wealthify are also competitive. Trading 212 does not yet offer a Junior ISA — a notable gap given its zero-fee adult ISA.
The 7 main UK Junior ISA platforms
| Platform | JISA platform fee | Min investment | Product range |
|---|---|---|---|
| Vanguard JISA | 0.15% capped at £375/yr | £100 lump or £100/mo | Vanguard funds + some ETFs |
| AJ Bell JISA | 0.25% (capped on shares £42; funds no cap) | £25 | ~2,500 funds + 1,000+ ETFs |
| Hargreaves Lansdown JISA | 0.45% funds; 0.45% ETFs capped £25 | £100 | ~3,500 funds + 1,000+ ETFs |
| Fidelity JISA | £25/yr fee (no platform percentage) | £25/mo or £50 lump | ~3,000 funds + ETFs |
| InvestEngine JISA | 0% on DIY; 0.25% on managed | £100 | 700+ ETFs |
| Wealthify JISA | 0.60% management + ~0.16% OCF | £1 | Managed portfolio |
| Beanstalk / Moneybox | 0.45-0.95% all-in | £1 | Managed |
| Trading 212 | Not available | — | — |
18-year cost comparison on £200/month
£200/month from birth to age 18 = £43,200 contributed. At 5% real annual return, this becomes ~£70,000 in real terms. Fee compounding matters because the pot grows for 18 years:
| Platform | Pot at age 18 (real terms) | Fees consumed over 18 years |
|---|---|---|
| InvestEngine DIY | ~£70,000 | ~£200 |
| Vanguard JISA (fund-heavy) | ~£69,000 | ~£1,200 |
| AJ Bell JISA | ~£68,500 | ~£1,800 |
| Hargreaves Lansdown JISA | ~£67,200 | ~£3,000 |
| Wealthify JISA | ~£65,500 | ~£4,500 |
The gap between cheapest and most expensive over 18 years is ~£4,500 — a meaningful headstart for the child if going low-cost.
What's different about a JISA vs adult ISA
- £9,000 annual contribution cap (vs £20,000 for adult ISA).
- Anyone can contribute — parents, grandparents, godparents, family friends. Useful for distributed gifting.
- Child can take control at 16 — can manage the account but not withdraw.
- Full access at 18 — JISA automatically becomes adult ISA, child controls and can withdraw fully.
- No partial withdrawals before 18 — money is locked. This is good for compounding but means choose carefully.
- Cash JISA and S&S JISA are separate — one of each per child per year. £9k cap applies across both.
The transfer-at-18 consideration
At age 18, the child can transfer the now-adult ISA elsewhere. If the JISA is on a less polished platform, the child may move it on their own initiative. Vanguard, AJ Bell, HL and InvestEngine all have apps the under-18s can use; Fidelity’s app is older but functional.
Decision framework
Best for cost-conscious lump-sum gifting
Best for: Grandparents wanting to give a meaningful sum at minimal cost
Vanguard JISA. 0.15% capped at £375/yr means even a £100k JISA pays just £150/yr. Vanguard's reputation reassures gift-makers.
Best for fund range
Best for: Investors wanting to pick specific funds beyond Vanguard's range
AJ Bell JISA. 2,500 funds + 1,000 ETFs at 0.25% fee. Better product range than Vanguard for less than HL.
Best for ETF-only, hands-off
Best for: Set-and-forget ETF portfolio managed automatically
InvestEngine JISA DIY. 0% fee, auto-rebalancing. Limited to ETFs but 700+ is plenty.
Best for tiny start-up amounts
Best for: Parents starting with very small contributions, want managed
Wealthify JISA. £1 minimum, 0.6% management. Cost is high but at small balances the absolute amount is small.
Best for "set once, forget" with fund choice
Best for: One-off lump-sum gift, parent doesn't plan to monitor
Fidelity JISA. £25/yr flat fee. Doesn't scale percentage-wise — better for small balances. Less polished app for the 16-18 transition.
Plan a JISA strategy
See the dedicated Junior ISA explainer on the kids subdomain — covering JISA mechanics, contribution rules and the 18th-birthday handover.
Open the Junior ISA guide →How we built this comparison
Fee and feature data is taken directly from each provider’s published website as of 2026-05-12. UK Tax Drag has no commercial relationship with any platform listed — no affiliate links, no referral codes, no sponsored content. The methodology page documents our comparison standards. The independence page confirms our funding model.
This page is educational only and is not regulated financial advice. The choice of platform depends on your personal circumstances, investment style, and balance. Always read the provider’s key facts document and verify the latest fees before opening an account. Past performance is not a guide to future returns. Investments can fall as well as rise.
Related
- Best ISA platform 2026/27 — adult ISA equivalent
- Lifetime ISA calculator — for children turning 18
- Compound interest calculator — project long-horizon JISA growth
- Junior ISA full guide (kids subdomain) — mechanics, switching, 18th birthday
- All investing content
- All calculators
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