Where on the globe would you best be able to sail a very large ship without being detected?

I’m working on a indie video game that’s set on a large ship and I’m looking to have it be a very hidden and elusive boat. (Speaking vaguely to avoid spoilers)

Where could it possibly be sailing through to avoid detection? Like no radars, land signals, etc..

There are slight sci fi elements that could explain it avoiding detection but want to make the location as believable as possible.

I’m not very familiar with oceans and the technology behind detecting vessels. Would love to be pointed in the right direction if anyone is knowledgeable.

Edit: Oh damn, this got a much bigger response than I expected. Thanks so much for all the awesome suggestions!

Edit2: Wow you guys have fantastic ideas! Just to clarify this is a real game project and not a joke or a cover for gold smugglers 😂

I am leaving hits and teases in my replies. Partially to have fun and build the world a little but also maybe get a bit of a community game going with a bread trail to follow. 😉🤫