The pair - from New Zealand and Spain - placed slices of bread on precise points either side of the planet, using longitude and latitude to make sure their measurements were exact.
Etienne Naude, from Auckland, came up with the idea and had wanted to make one for "years" but was unable to find someone at the other end.
He was eventually able to contact a Spanish counterpart using Reddit, although he admitted the stunt was "hard to organise" because of the time difference between the two nations.
Naude said: "It was quite hard to organise since it's a 12-hour time difference. And there's lots to arrange, such as the kind of bread, the time, the (precise) location, et cetera."
He also struggled choosing the appropriate spot for his side of the sandwich.
He explained: "It's quite tough to find a spot which isn't water on the New Zealand end - and where public roads or paths intersect in both sides."
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