The promising defender arrives from Motsepe Foundation Championship side Casric Stars, further strengthening Eric Tinkler's squad ahead of the 2025/26 campaign.
Thokolo's arrival marks a significant reinforcement for the club, who have matched their number of signings with 11 departures in the same window.
Among those departing are two loanees, Katelgo Otladisa and Sipho Mbule, as Tinkler reshapes his side with a clear intent to build on last season's progress.
Casric Stars, Thokolo's former club, finished third in the 2024/25 Motsepe Foundation Championship but failed to secure promotion via the playoffs.
They were ultimately outdone by Orbit College and Cape Town City - the latter suffering relegation despite participating in the playoff group.
Sekhukhune United, who finished fourth in the DStv Premiership last season, are now preparing to kick off their campaign in the MTN8.
They face TS Galaxy, who ended the 2024/25 season just one place below them in fifth. The match is scheduled for Saturday, 2 August 2025, at the Peter Mokaba Stadium, with kick-off set for 18:00.