Cell phones are allowed on the course—kind of.

Two-way communication devices, such as walkie-talkies and cell phones, have long been banned on the race course. It’s been a difficult rule for officials to enforce, especially as more and more athletes use their cell phones for bike/run data or race-day tracking. As a sign of the times, Ironman will now allow cell phones on the course, but that isn’t an open invitation to live-tweet your race: athletes using cell phones in a “distractive manner”—in their words, “making and receiving phone calls, sending and receiving text messages, playing music, using social media, taking photographs and mounting the device to a bike for purposes of using the device like a bike computer.”—will be disqualified.