To answer this question, an international team of researchers looked for the origins of the tarantula group more than 100 million years ago, building a family tree. Once they created the family tree, they assigned a time axis to the spider fossils, thus estimating how and where the first tarantulas appeared and dispersed. Likewise, the results of the study were published in the journal PeerJ.
Scientists discovered that tarantulas first appeared during the Cretaceous period (in what is now America). But back then, America was part of the massive supercontinent Gondwana. The ancient tarantula relatives probably spread across the supercontinent, dispersing from America to Africa, Australia, and India. However, when Gondwana began to fragment, India broke away from Madagascar and collided with Asia, so the spiders they also traveled to that territory.
On the other hand, because tarantula fossils are so rare, the researchers had to collect mygalomorph data, a group of arachnids that includes tarantulas and other large ground-dwelling spiders. Thus, after building the tree from all this information, the scientists adjusted the time using the fossil data.