The $1 airport bus nobody tells you about

A Grab from Noi Bai into central Hanoi typically runs 180,000–300,000 VND (~$7–11). The public buses covering the same ground cost 45,000 VND (~$1.71) in Hanoi and 15,000–20,000 VND (~$0.57–0.76) in HCMC — that’s $5–7 per person back before you’ve even checked in.

The play:

1. HCMC: from Tan Son Nhat, board air-conditioned bus 109 outside the arrival hall. It runs direct to District 1 and the tourist areas in about 45 minutes, roughly 5:30 AM–10 PM.
2. Hanoi: take bus 86 from Noi Bai to the Old Quarter or the railway station — about an hour, with departures every 15–30 minutes, roughly 6:40 AM–10:15 PM.
3. Use the bus to skip two lines at once: the taxi queue and surge-priced Grab. The fare is fixed no matter when you land.

Price anchor: as of mid-2026, bus 109 (HCMC) costs 15,000–20,000 VND (~$0.57–0.76) and bus 86 (Hanoi) costs 45,000 VND (~$1.71), against a typical Grab airport run of 180,000–300,000 VND (~$7–11) (fare reports vary — being re-verified).

Verified: sources (2024–2026), 2026-07.