Nostoi and the Sea of Bygone

Nostoi Region and the Sea of Bygone Areas in Genshin Impact

This is our hub page for Genshin Impacts Nostoi Region and the Sea of Bygone Eras additional map. Here you can find information about Oculi locations, Puzzles, Chests, Time Trials and more!

Last updated on Apr 24, 2024 at 10:50 by Shikhu

Nostoi and the Sea of Bygone Eras 4.6 Exploration

Patch 4.6 released 2 new explorable regions with a whole host of Hydroculus, chests and puzzles available.

This is split into 2 regions which you can 100%.

  • Nostoi - Contains the town of Petrichor and the Faded Castle.
  • Sea of Bygone Eras - A separate underwater map unlocked during this Regions World Quest.

It is highly recommended that you complete the World Quest before heading off to explore, however you will likely collect some Oculus and chests while completing this quest.


Ancient Autoharmonic Music Box

The Ancient Autoharmonic Music Box is an ancient music box found inside of the Faded Castle. This grants you the power of the Symphony for exploration as well as providing Primogems as you collect each of the six scores available.


The Nostoi Region

Nostoi is the overworld half of this region featuring Petrichor and the Faded castle. It is a very small area with not many chests or collectables available.


Nostoi Region Special Puzzles and Collectables

Listed below are our pages for special puzzles and collectables available inside of the Nostoi Region.


Sea of Bygone Eras

The Sea of Bygone Eras is accessed via the World Quest unlocked at the beginning of Petrichor. With the Sea of Bygone Eras being a separate map much like Enkanomiya and The Chasm but this time is almost entirely underwater.


Hydro Sigil Shop

The release of patch 4.6 also comes with a Hydro Sigil shop so that you can spend any excess Sigils not used in the Fountain of Lucine.

A very welcome change with Fontaine's exchange is that you are able to buy an unlimited amount of Weapon Ascension Materials with any remaining sigils. Historically, there has only been Mora available but this change can be a nice boost in resources for players who still have a range of Fontainian weapons to upgrade.



  • 24 Apr. 2024: Guide added.
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