The Port of Oakland's free 90-minute harbor tour has two twilight dates left this season — Sept. 25 and Oct. 16. Tickets are gone in minutes. Here's how to actually get on board.

The most coveted ticket in the Bay Area this fall costs nothing and takes you to stare at cargo cranes. Two dates remain in the Port of Oakland's free harbor-tour season — Friday, Sept. 25 and Friday, Oct. 16, the last cruise of the year — and if you want a seat, the hard part isn't the outing. It's the on-sale.

Start with the specifics, because they're the whole game. Both cruises run 5:30 to 7:00 p.m., a 90-minute narrated loop through the Oakland Estuary and out onto the Bay aboard a Red and White ferry — and note that's earlier than the summer sailings, which ran 6:45 to 8:15. Boarding is at the Oakland Jack London ferry terminal, 10 Clay St. at Water Street, in Jack London Square. Free registration for Sept. 25 opens Tuesday, Sept. 15 at 8 p.m.; the Oct. 16 window opens Tuesday, Oct. 6 at 8 p.m. Each window lands exactly 10 days ahead of its tour, each person can reserve up to four passes, and the Port takes no phone reservations.

That last detail matters, because demand is brutal. The Port's own harbor-tours page↗ (external source, opens in a new tab) warns that the free tickets "are usually all taken within minutes" of registration going live. Here's what all that scrambling buys: a genuinely odd 90 minutes in which you glide past the giant ship-to-shore cranes while a guide walks you through how the Oakland Seaport lifts a single container off a ship and onto a truck. The tours have run each year from spring through October, Bay City News reported↗ (external source, opens in a new tab), narrating the estuary, the working terminals, and the port's history along the way. The price is exactly zero, which is the entire reason it's so hard to get.

The insider move. Treat 8 p.m. on registration night like a concert on-sale: have the Port page loaded before the clock turns, know how many passes you want, and commit fast. If you whiff, you're not done — the Port runs a walk-in waiting list. Show up at the dock 30 minutes before departure and ask to be added; per the Port, standby riders have made it aboard in past years as no-shows accumulate. It's a gamble, but a free one, and a 5:30 weekday start is prime flake territory for reservation-holders stuck at work.

A few practicals worth knowing. There's paid parking in the Jack London Square lots, but the cleaner arrival is BART to 12th Street/Oakland City Center — about a 12-minute walk down to the water. Bring a layer; you're on open water at sundown heading into October.

If you only get one shot, make it Oct. 16. It's the season finale, the low autumn light throws the longest shadows off the cranes, and once it's gone the next tour isn't until May. Set the alarm for 7:55 p.m. on Oct. 6 and don't wander off.