Of the English-speaking iterations of the Survivor franchise, the two most popular versions have yet to complete a full crossover, but that could change with a possible "US vs. Australia" All-Star season. The American version of the show has been a reality television juggernaut since premiering in the summer of 2000. The first few seasons were enormous ratings hits, leading Survivor to be one of the most watched TV shows of its time, as well as a pop culture phenomenon. Although its mainstream popularity has decreased over time, Survivor is still a ratings hit and remains one of the most popular CBS shows.
Australian Survivor, on the other hand, has had a less straightforward path to success. Capitalizing off of the immense popularity of the American version, the series premiered in 2002 on Network Nine. However, due to low ratings and poor reviews, it was canceled after the first season. Network Seven debuted a celebrity edition in 2006, but like its predecessor, it also only lasted a season before cancellation. In 2016, Network Ten premiered its version of Australian Survivor, which has built a loyal following, and has spawned seven seasons so far.
Fans of both franchises have long been clamoring for an international crossover All-Stars event between the US and Australian versions, and it's certainly not an impossibility. The most probable path for such a season to take place would be for it to happen in an Australian Survivor season. It's unlikely that the American version would invite Aussie Survivor vets to play on CBS, for a number of reasons, the most obvious being that the vast majority of American viewers don't have any familiarity with Australian Survivor. Therefore, they wouldn't be familiar with any of the players (or their stories) coming into the season. On the other hand, the US version of the show airs in Australia and has a sizable following in the country, so Australian Survivor fans would be far more likely to be invested in returning players from both franchises.
Furthermore, Australian Survivor has already included two American greats in previous seasons. Infamous villain Russell Hantz played in Australian Survivor: Champions vs. Contenders in 2018, while Russell's Heroes vs. Villains nemesis (and two-time winner) Sandra Diaz-Twine, competed on the most recent Aussie season: Blood V Water. Clearly, the Australian Survivor producers are willing to extend an international invite to complete their casts. The Blood V Water season was maligned by fans, and the show began to dip in viewership. For this season, producers might be looking to revitalize the series with a major event season. An international showdown could definitely fit the bill in that regard.
The prospect of an international All-Star season is definitely thrilling for hardcore Survivor superfans. The possibility of seeing Aussie greats like David Genat, Luke Toki, and Hayley Leake battling it out with US names like Cirie Fields, Ozzy Lusth, or Second Chance candidate Teresa "T-Bird" Cooper is enough to sell the season. It would also provide an opportunity for some American standouts to return to the game, despite being unlikely to get a call from CBS. An iconic player like Jonny Fairplay, for instance, whose relationship with host Jeff Probst is famously turbulent, might be more likely to get invited to play on Australian Survivor than he would be in the States. Because of these factors, the idea of a major international Survivor crossover is one that is full of exciting possibilities that could become a reality sooner, rather than later.