Bilbao to Gaztelugatxe by Bus
The Bizkaibus route from Bilbao to Gaztelugatxe: line A3518 to Bakio, the weekday-only A3524 connection, the summer direct service, and when the bus is a bad idea.
You can reach San Juan de Gaztelugatxe from Bilbao on public transport for a few euros. Whether you should depends almost entirely on two things: what day of the week it is, and what month. On a weekday in July it is straightforward. On a Sunday in November it is a 40-minute bus ride followed by a three-hour round-trip walk.
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Leg one: Bilbao to Bakio on line A3518
Line A3518 departs from Plaza Moyua in central Bilbao, runs via Mungia, and reaches Bakio in roughly 40 minutes. Service is around hourly. This leg is reliable, frequent enough to plan around, and the easy part of the day.
It also, crucially, does not get you to Gaztelugatxe. Bakio is a beach town about 6 km short of the site.
Leg two: Bakio to the islet — the awkward part
Line A3524 covers Bakio–Gaztelugatxe–Bermeo on weekdays only, roughly every two hours from early morning to early evening. It is an eight-seat taxi-bus, not a coach, and it takes cash. Eight seats is a real constraint in August. The stop for the site is Gaztelubegi.
In high season a direct Bilbao–Gaztelugatxe service, line A3517, appears and removes the connection entirely; frequencies rise across the network over the same period.
Otherwise you walk. Bakio to the Gaztelugatxe entrance is roughly 5 to 6 km, uphill, around an hour and a half each way — a pleasant coastal walk in good weather, a grim one in Atlantic rain, and you do it twice, before and after the 241 steps.
Bizkaibus timetables change seasonally and at short notice. Check the current route and times on the operator’s own site before you travel; treat every figure here as an indication, not a schedule.
What the day actually costs you in hours
Work backwards from the last useful connection, not forwards from the first.
A weekday in season, with the A3524 running: roughly 40 minutes to Bakio, up to two hours of waiting depending on where your arrival falls in the cycle, 15 minutes on the connection, then about two hours at the site, then the same in reverse. Call it six to eight hours door to door for two hours of visit — and the wait is unavoidable, because the two services are not timed against each other.
A weekend outside summer, walking: 40 minutes, an hour and a half up, two hours at the site, an hour and a half back, plus the wait for the return bus. Nine hours is realistic, and you will have walked 12 km on top of the 241 steps.
Compare that with the 3.5-hour small-group tour, which does the whole thing including transport and entry, or the six-hour trip at $63 that adds two villages. The bus does not save you money so much as trade money for a whole day.
The thing the bus does not solve
Public transport gets you to the entrance. It does not get you in.
On the busy dates — daily through summer, weekends from late March to the end of October, plus Easter, Christmas and Spanish public holidays — you need a free timed reservation from the Bizkaia provincial council, booked in advance, with a daily cap on numbers. Arriving on the A3518 without one on one of those days means standing at the gate.
Worse, the reservation is a start time, and it is cancelled 60 minutes after it. Pinning a fixed slot to a two-hourly connecting shuttle with eight seats is exactly the kind of plan that fails on a bad day. If you are going by bus in season, book an early-afternoon slot with plenty of margin — and read tickets and reservations first.
When the bus is genuinely the right call
It is, in three situations, and it is worth saying so plainly.
You have a spare weekday and a tight budget. With the A3524 running, the trip works, the fare is trivial, and the walk-in from Gaztelubegi is short.
You want the Bakio coast walk for its own sake. The path between Bakio and the site is a genuine coastal walk with cliff views most tour passengers never see. If the walking is the point rather than the obstacle, doing it on foot is the better day.
You are already staying in Bakio or Bermeo. From either, the connection is short and the whole calculation changes.
Outside those cases — weekends off-season, high summer with a fixed slot, anyone with limited time in Bilbao, or a group that has to move together — a guided departure wins on hours rather than on euros. How to get to Gaztelugatxe from Bilbao sets the bus against the car and the tour on the same table, and the which tour guide picks a departure if that is where you land.
See Dragonstone for Real — From Bilbao, in a Day
Rated 4.7/5 by more than 3,000 guests. Bilbao pickup, guaranteed Gaztelugatxe access, Bermeo, Mundaka, Gernika and a txakoli tasting. Free cancellation up to 24 hours before.
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