The catch was caught on video thanks to the roller coaster's souvenir photosystem.
The lucky owner of the flying phone bought the clip for Kempf to remind him of his unbelievable catch.
Kempf, who hails from New Zealand, was in Europe for the Fistballing World Championship, Stuff, a news outlet in Kempf's home country, reported. Fistball is a sport comparable to volleyball.
"The guy two rows ahead of me, as the ride started doing its ascent before it drops, he had his phone out and he dropped it and it just landed at the bottom of his cart," Kempf said.
"He was trying to reach down and grab it but because he was locked in he couldn't reach it and I just jokingly said to my brother and the people we were with 'Get ready to catch'," Kempf said.
Kempf told Stuff he had forgotten about the phone for a moment until it was flying past his cousin's head.