A list of frequently asked questions, including information about refunds and rebooking, was published after it was announced strikes will happen on 9, 10 and 27 September.
The airline said it was "likely" anybody booked on those days will not be able to travel.
It said: "We will be offering all affected customers full refunds or the option to re-book to another date."
Passengers should find out via email whether their flight is definitely cancelled. They will also be given advice about refunds and rebooking, the advice on britishairways.com says.
Options on what to do next can also be found by logging into the BA website and visiting the Manage My Booking page.
People affected by the final strike, on 27 September, will be contacted "within a few weeks".
BA told customers: "We are committed to offering as many customers as possible the option to rebook on partner airlines.
"If your flight has been cancelled, you can also request a full refund, or opt to rebook your flight on another time in the next 355 days, or use the value of your fare to fly to a different destination.
"If you are travelling on one of the impacted dates, but your flight has not been cancelled, you can opt to rebook your flight at another time in the next 355 days."