First, 27-year-old Australian Dwight Beare was killed. In Sidecar TT Race #1, he was involved in an accident around Rhencullen with co-driver Benjamin Binns. Binns was transported to a local hospital for an ankle injury and is described as being in "stable" condition in a statement.
Beare first competed in the event in 2014 alongside his father, placing 12th in the second race. He returned last year, finishing 17th.
Later, Englishman Paul Shoesmith also lost his life, crashing on the Sulby Straight during practice. He was 50. The session was consequently suspended.
Shoesmith was a veteran of the event, having made his TT debut in 2005. His best showing came in 2011 when he placed 15th in both the Superbike and Senior races.
They are the 249th and 250th competitors to be killed on the Snaefell Mountain Course.
It continues a sad weekend for the world of motorcycle racing. 24-year-old Moto2 rider Luis Salom was killed Friday during practice at Circuit de Barcelona-Catalunya.
This article by Nick DeGroot originally appeared on Motorsport.com.