Sea of Thieves Season 20 Adds Custom Seas Mode June 18

Sea of Thieves Season 20 kicks off on June 18, introducing Custom Seas. This new set of tools allows players to reshape Rare’s pirate sandbox into almost any game mode they can think of. It even includes machinima creation capabilities that push the feature beyond typical custom lobbies.

With Custom Seas, players gain control over key aspects of the shared world. They can modify enemy spawns, weather conditions, crew rules, and session parameters. The machinima tools complement these options, enabling content creators to stage and film scenes right within the game engine. As PC Gamer puts it, this update turns the game into “a saltier sort of sandbox.”

This update comes nearly eight years after Sea of Thieves launched in March 2018. The game now has a complex public image. Its Steam rating stands at 88% positive based on 166,548 reviews, which is solid overall. However, recent player sentiment has turned negative, with many expressing frustration over monetization issues. The base game is priced at $13.99 on Steam, but the in-game store has become a frequent topic of debate within the community.

Custom Seas marks a significant structural change for the game. Most live-service games typically limit custom game tools to creator programs or competitive modes. However, Rare is making this feature available to all players. Whether this leads to an increase in the game’s current 10,648 concurrent players on Steam will become apparent in the weeks after launch.

The announcement of Season 20 also comes amid some serious issues off the field. In May 2026, a well-known Sea of Thieves creator faced a ban due to serious allegations, casting a shadow over the community as summer content approaches. Rare hasn’t publicly addressed this situation in relation to the Season 20 launch.

By The Numbers

Season 20 Launch Date	June 18, 2026
Steam Review Score	88% positive (166,548 reviews)
Current Steam Price	$13.99
Current Concurrent Players (Steam)	10,648
Metacritic Score	68
Original Release Date	March 20, 2018

Community reactions have sharpened over time. One Steam reviewer, who has put in significant hours, remarked, “it’s like the dev team is just bent on making the game worse.” They added that “content updates are focused on squeezing as much money out of players as possible.” The Custom Seas feature, which offers player-facing tools instead of premium content, might be Rare’s way of changing that perception. However, it needs to resonate well to improve recent sentiment trends.

What To Watch

• Keep an eye on whether Custom Seas results in a noticeable increase in concurrent player counts on Steam and PS5 in the two weeks following the June 18 launch. Sustained engagement will be more important than just a quick day-one boost.
• Check how comprehensive the machinima toolset is at launch, and whether Rare plans to expand it in future seasons based on creator usage.
• Watch for signs that Season 20’s focus on player empowerment indicates a shift in content strategy away from the premium cosmetic model that has led to recent negative reviews.