Sea of Thieves Custom Seas
Custom Seas launched with Season 20 on 18 June 2026 and is free for everyone who owns Sea of Thieves, despite originally being announced as a paid subscription feature. The session owner gets admin control over a private server: assigning crews to ships, setting weather and time of day, spawning NPCs, creatures and treasure, toggling world events on and off, and defining scoreboards and win conditions. A cinematic free camera is included for recording.
Rare spent years telling players that private servers were not happening. Custom Seas is the reversal, and it arrived in a stronger form than most people expected, since the announced subscription price was dropped before launch.
What is Custom Seas?
A private Sea of Thieves session where one player is the Session Owner and holds admin controls over the world itself. Nobody joins uninvited. The host decides what the session is.
That makes it fundamentally different from the other two modes. Safer Seas removes other crews. High Seas gives you the full game with all its risk. Custom Seas hands you the toolbox and lets you build whatever you want. Full comparison of the other two is in Safer Seas and High Seas.
Custom Seas is free for all Sea of Thieves owners. It was first announced with a subscription model attached, and Rare reversed that before it shipped. Any article describing it as a paid add-on predates the change.
What can the session owner actually control?
| Control | What it does |
|---|---|
| Crew assignment | Place players onto specific ships |
| Weather | Set conditions, including storms |
| Time of day | Lock it to day, night, or anywhere between |
| NPC and creature spawning | Place skeletons, animals, and sea creatures |
| Treasure placement | Put specific loot exactly where you want it |
| World events | Turn individual events on or off |
| Scoreboards | Track whatever the session is scoring |
| Win conditions | Define what ends the session and who won |
| Free camera | Cinematic camera detached from your pirate |
Taken together those are the ingredients for a game mode editor, not just a private lobby.
What is it actually good for?
Practicing ship combat. Two crews, a scoreboard, repeated fights with no loot at stake. This is the single biggest use, because open-world PvP gives you maybe one fight an hour and Custom Seas gives you as many as you want.
Learning the ropes without pressure. Set permanent daylight, calm weather, no events, and teach a new player to sail. That is a far kinder introduction than the Maiden Voyage plus a live server.
Content creation. The free camera plus weather and time control is a proper filmmaking kit. Sunset chase footage without waiting for an actual sunset.
Running events. Races, treasure hunts, custom tournaments, and whatever else a group invents. Scoreboards and win conditions exist precisely so these can be scored properly.
Practicing world events solo. Spawn a fort, learn the wave patterns, and repeat it without another crew arriving.
The highest-value thing most crews can do with Custom Seas is drill the fundamentals. Anchor turns, chain shot accuracy, boarding timing, and the patch-then-bail order all improve fastest with repetition, and repetition is exactly what the live game never gives you.
How does it compare to the other modes?
| High Seas | Safer Seas | Custom Seas | |
|---|---|---|---|
| Other crews | Up to five | None | Invited only |
| PvP | Always possible | Never | Host decides |
| World control | None | None | Full |
| Who sets the rules | Rare | Rare | You |
| Best for | The real game | Learning and Tall Tales | Practice, events, filming |
What to know before hosting
You are the admin, so you are the referee. Scoreboards and win conditions do not enforce sportsmanship. Agree the rules with the group first.
Session control sits with one person. The owner's connection and their decisions shape everyone's session, so hand hosting to whoever has the most stable connection.
It is not a progression shortcut. Treat it as a practice range and a stage rather than a way to farm, and check the current rules yourself before assuming any session rewards carry over.
Frequently Asked Questions
Is Custom Seas free in Sea of Thieves?
Yes. It launched with Season 20 on 18 June 2026 as a free feature for everyone who owns the game. It was originally announced with a subscription model, and Rare reversed that decision before release, so older coverage describing it as paid is out of date.
What can you control in a Custom Seas session?
The session owner can assign crews to ships, set weather and time of day, spawn NPCs, creatures and treasure, toggle individual world events on or off, define scoreboards and win conditions, and use a cinematic free camera for recording.
What is Custom Seas best used for?
Practicing ship combat with repeated fights and no loot at risk, teaching new players in controlled conditions, filming with the free camera plus weather and time control, and running group events like races and tournaments with proper scoring.
How is Custom Seas different from Safer Seas?
Safer Seas is a fixed private session with Rare's rules and no other crews. Custom Seas is a private session where the host controls the world itself, including weather, spawns, events, and win conditions, and can invite other crews in to compete.
When did Custom Seas release?
18 June 2026, alongside the launch of Season 20, following a short server maintenance window. It shipped as part of the same update that restructured the season pass to 50 levels across 10 tiers.
What to Read Next
- Safer Seas and High Seas. The other two modes in full, and what each one locks.
- Seasons and Events. Season 20, which shipped Custom Seas, and how the season structure changed with it.
- Ship Combat and Damage Control. The skills worth drilling in a custom session.
- PvP and the Hourglass of Fate. Where that practice gets tested for real.
- Getting Started. The basics to learn before hosting anything.