Tonia Couch and Sarah Barrow, should they navigate Wednesday evening's preliminary round, plunge for a place in the women's 10m platform final - which is scheduled for 8pm.
Jade Jones, Britain's first-ever Olympic taekwondo champion, starts the defence of her London 2012 title in the women's -57kg category against Morocco's Naima Bakkal. Should Jones make the gold medal match, it will be a 2am bout.
Alistair Brownlee seeks to retain his London 2012 triathlon title with brother Jonny - bronze medallist four years ago - likely to be in hot pursuit.
Marcus Ellis and Chris Langridge have the chance to claim Great Britain's first Olympic medal in badminton since 2004 when they face Chinese duo Wei Hong and Biao Chai in the men's doubles bronze medal match.
Sailors Dylan Fletcher and Alain Sign, currently fourth, will be looking to force their way onto the podium in the 49er men's medal race.
Reigning Olympic flyweight champion Nicola Adams, who is guaranteed at least a bronze medal, faces China's Cancan Ren in the semi-finals.
Usain Bolt will be bidding for his second gold in Rio - and eighth in the Olympics in total - should he do the inevitable and make it through Wednesday night's semi-finals. Britain's Adam Gemili will also be vying for a podium place in the event while Eilidh Doyle goes in the women's 400m hurdles final at 2:15am.
Brazilian pair Alison Cerutti and Bruno Schmidt go for gold in the men's beach volleyball final against Italy's Paolo Nicolai and Daniele Lupo on Copacabana beach.