The date and a fuller look at the expansion were revealed during the PC Gaming Show Tokyo Direct, as reported by PC Gamer. For existing PC players, the important point is that Deep Water is still positioned as free DLC, but it requires the base game on Steam.
What Deep Water adds
The expansion introduces three climbing areas: the Haken and Ruka cliffs, plus the Lamu climbing gym. Haken and Ruka are built around climbing above water, a new setup that changes the consequence of falling. Rather than ending a run through the usual fatal fall state, a missed hold can send the climber into the water and allow another attempt.
That does not mean the new areas turn Cairn into a consequence-free climbing game. Route choice, stamina management, positioning, and movement control remain central to the base game’s survival-climbing design. The water element instead gives players room to practice difficult overhangs and experimental routes without the same cost attached to every error.
Lamu serves a different purpose. The climbing gym is a controlled environment for tackling new climbing problems, offering an alternative to learning solely on exposed outdoor routes. Players who want to understand movement options before committing to a longer mountain ascent should get more practical value from that space than from the water-soloing locations.
Marco and free-roam practice
Deep Water also adds Marco as a playable climber. According to PC Gamer’s report from the Tokyo Direct reveal, his climbing style differs from protagonist Aava’s, although the announcement does not yet spell out the mechanical differences in detail. Players should therefore treat Marco as a confirmed new character option, rather than assume that he introduces a separate campaign or a radically different control system.
The DLC’s other substantial addition is a free-roam mode for both characters. It will let players reload mountain saves, revisit sections, practice lines, and try alternative routes. That is a useful fit for a game where route planning and execution are closely tied together: instead of treating a route as a one-shot progression obstacle, players can return to it as a climbing problem to study.
A delayed release, but a more concrete plan
The Game Bakers first announced On the Trail: Deep Water in April as the opening entry in a series of free Cairn expansions. At that stage, the studio described three new locations and water soloing, with a summer 2026 release target for PC and PlayStation 5.
Steam’s previous listing information still reflected an earlier August date in some indexed results, while the store page has since shown the DLC as coming soon. The October 29 announcement is therefore the date PC players should use for planning, rather than the older summer window or stale August listings.
For Cairn owners, there is no separate upgrade decision implied by this release: the DLC is free, and its additions are aimed at extending the base game with new environments, another climber, and a more forgiving place to refine technique. Players waiting specifically for repeatable practice routes and climbing-over-water challenges now have a firm date: October 29.