This is the most useful paragraph on the page and the one visitors most often skip.
The crossing is weather-limited by design. The operator suspends sailings when winds exceed roughly thirty-five miles an hour or seas exceed about six feet, which on a bay entrance in a northerly blow happens several times a winter and occasionally in summer ahead of a system.
Beyond weather, the service has a history of longer stoppages. It was suspended in April 2020 during the pandemic, and there have been other temporary shutdowns since, including in 2023. A car ferry across a shipping channel is an expensive thing to run for a small population, and the funding and operating arrangements have not always been stable.
The practical rules, in order.
Check the day you intend to travel, not the week before, and check the operator's own updates rather than a third-party listing.
Have a plan B that does not involve the crossing. If you are on the Gulf Shores side, that plan is the fort, the refuge and the peninsula beaches, which is a good day anyway. If you are on the Dauphin Island side, it is a three-hour drive.
And if you are catching a specific return sailing, be at the landing early. Missing the last boat of the day on the wrong side of Mobile Bay is a long, expensive evening.