After missing out on a medal yet again in the men's 100 metres at the 2024 Paris Olympics – finishing fourth with a new South African record time of 9.82, Simbine finally won an Olympic silver medal as part of South Africa's 4 × 100 metres relay team on 9 August 2024.
Simbine won the 2018 Commonwealth Games 100 m final in 10.03 seconds, relegating pre-race favourite Yohan Blake into third.
2020
Simbine started his 2020 season with a 150 metre race at the University of Johannesburg Stadium on 14 February, equalling the South African record time (15.08) while jogging to the finish line, but with no wind information.[11][12] He ran his first 100 m for the season on 14 March at the University of Pretoria Tuks Stadium. Unsure whether or not he would be able to compete later in the season because of the rapidly spreading COVID-19 pandemic, he pushed to the finish line in a world-leading time of 9.91 seconds in the heats.[13]
Simbine stopped track training in March and didn't get permission to resume training again until July, weeks after other sports had resumed training after he pleaded with Athletics South Africa to allow athletes back onto the track.[14][15] He would not be able to compete until leaving South Africa in mid-August for Europe, winning a series of 100 m competitions in Marseille, Rovereto, and Bellinzona in times of 10.19, 10.17, and 10.02 seconds respectively. He finished his season in September with a 100 m victory at the Rome Diamond League, trailing Arthur Cissé of the Ivory Coast for the first 85 m before passing to win in 9.96 seconds.[15]
2021
Simbine started the season with a 10.00 seconds win in the 100 metres at the Athletix Invitational in Johannesburg on 23 March, which would have been a leading time but for the wind velocity, which was just over the allowable +2.0 m/s limit.[16] He broke 10 seconds at the Gauteng North Championships at the University of Pretoria on 27 March, winning 9.99 seconds ahead of Gift Leotlela (10.20) into a –3.0 wind. According to SuperSport, Simbine claimed that the "windy conditions were some of the worst I ever raced in."[17]
On 15 April at the South African Championships in Pretoria, Simbine competed in the men's 100 metres, finishing his first round heat in 10.11 seconds. He then won his semi-final in 9.82 seconds, the fastest he had ever run, but the wind was again over the limit for record purposes at +2.8 m/s.[18] The next day, he clocked his 29th sub-10-second time with 9.99 seconds to win the final, finishing 0.17 seconds ahead of second placing Gift Leotlela's 10.16 seconds.[19]
Two weeks later, on 2 May, Simbine anchored South Africa to gold in the men's 4 × 100 metres relay at the 2021 World Relays. He received the baton three metres behind Brazil's Paulo André de Oliveira but managed to close the gap and finish one-hundredth of a second ahead of Brazil with a time of 38.71 seconds.[20]
On 6 July, racing at the Hungarian Athletics Grand Prix, Simbine set a new national and African record of 9.84 seconds in winning the final.
On 1 August, at the 2020 Summer Olympics, held in Tokyo, Japan, Simbine finished fourth in a time of 9.93 seconds, behind winner Lamont Marcell Jacobs of Italy, with a time of 9.80 seconds.[21]
2024
On 4 August, Simbine missed a podium finish in his third consecutive Olympic 100-metre final at the 2024 Summer Olympics, setting a national record of 9.82 seconds in fourth place.[22]
On 9 August, Simbine finally won an Olympic medal as part of the South African 4 × 100 metres relay team by claiming silver.