1. The Elizabeth Line (£13.90 · 30–38 min) — Best Overall for Most Travellers
Air-conditioned, step-free walk-through trains run directly from Heathrow through Paddington (29 min), Bond Street (33 min), Tottenham Court Road/Soho (35 min), Farringdon (39 min), and Liverpool Street (43 min). Tap in with Contactless, and the £13.90 fare counts toward your Zone 1–6 daily cap (£15.60).
2. Piccadilly Line Underground (£5.60 · 50–55 min) — Best Budget Direct to South Kensington & Covent Garden
Direct Tube trains serve South Kensington, Knightsbridge, Piccadilly Circus, Covent Garden, Holborn, and King's Cross St Pancras for just £5.60 contactless.
3. Heathrow Express (£25 walk-up / from £10 Advance · 15 min) — Fastest to Paddington Only
Nonstop 15-minute shuttle to London Paddington every 15 minutes. Only worth the premium if staying beside Paddington or booked 45+ days early for £10–£15 Advance fares (note: Heathrow Express does not count toward TfL daily fare caps).