Not all of the Frozen 2 Teaser Trailer takes place in Arendelle.

Photo Credit: p1nkblu3 on Flicker (left) and Yiannis Pavlis on Flickr (right). The photo on the left is originally by Disney. The photo on the right is Vik i Myrdal in Iceland.

In the beginning of the trailer Elsa is on a beach with black sand. Beaches in Norway and Denmark have white sand, even if the beach in The Little Mermaid did not. Norway is where Frozen was set. For the Denmark connection see my previous article here.

Beaches in Iceland have black sand. Iceland is west of Norway and was originally settled by Norwegians. This fits with the synopsis of Frozen 2, of wanting to find out about the secrets or possibly the origin of Arendelle.