Applicable version: as of the 2026-10-09 update (this game has no version numbering system)
Arknights Yesterday Sea event schedule: October 9 opening to October 30 close
Yesterday Sea is October's Side Story. It went live after the October 9 06:00 maintenance, and both the stages and the exchange shop stay open until October 30 at 03:59 . Almost three weeks is roomy, but do not leave it to the final week.
What shipped in the same update
The update packed events, banner, outfits, furniture and base features together: the Yesterday Sea stages, the Skyward Cruise limited headhunt, trust boosts for the new operators, the Misshapen Procession outfit line plus a re-run outfit gallery, the Harbor Club lounge furniture set, and two new base rooms. Existing players should treat this as one combined check-list rather than five separate chores.
Where to start
Anything with a deadline comes first. Stages and shop close October 30, outfits and furniture are limited-time, and daily login rewards cannot be back-filled . So: claim logins, push stage progress, then think about the banner. If you are mapping Arknights best teams around the new unit, settle the free operator first.
Arknights Yesterday Sea Clementha pull value: what a Vanguard-Lane Guard does
Clementha is the only new six-star this cycle. She is a Vanguard-Lane Guard who deals burst damage through Corrosion, and she also brings push and pull control . Community tier talk about her always lands on the same two points: a very high ceiling, and a team that has to be built around her.
How skill three works
Her third skill uses an ammo mechanic. When Corrosion bursts on enemies across the field, it triggers a pseudo-global cross-shaped strike. Community testing puts the theoretical total damage above 330,000 . That number is eye-catching, but it only happens if you have already stacked Corrosion.
The pull threshold
On the limited headhunt, Clementha takes 50% of the six-star rate, while the five-stars Del Toledo and Firewatch together take 50% of the five-star rate . Fifty percent means a miss is a miss, so work out your pity budget before you pull.
The reason to hold back is that a Vanguard-Lane Guard needs partners: someone to catch what she pushes, someone to stack Corrosion. Without that, skill three never reaches its theoretical output.
Arknights Yesterday Sea free operators: how to use Core Tactician
The free five-star Core Tactician is a Specialist-Alchemist. The talent lowers the physical and arts accuracy of ground enemies inside the alchemy unit's range, and the skills lean toward slow and sustained arts damage . Zero cost, so build it.
Why the free unit matters
The most overlooked lesson for newer players is that free operators are not judged on raw power but on how precisely they counter a problem. Core Tactician's accuracy cut is strong in specific maps and enemy compositions .
Should you chase Del Toledo
Del Toledo occupies a five-star rate-up slot with limited general value, so there is no reason to spend pulls specifically for him . Keep him if he arrives while you pull for Clementha.
Arknights Labor Ration Exchange priority: non-renewable first
The event shop is called the Labor Ration Exchange in the community. The logic is identical to every Side Story: take the non-renewable items first and leave anything your base produces on its own for last .
Exchange order
| Priority | Item | Reason |
|---|---|---|
| 1 | Limited operator tokens, event furniture | Gone for good once the shop closes |
| 2 | Module and promotion materials | Slow to farm normally, a real bottleneck |
| 3 | Generic ascension materials | Available elsewhere, can wait |
| 4 | Pure resources like Lungmen Dollars | The base produces them steadily |
How much sanity per day
Sanity regenerates at one point every six minutes, roughly 240 points a day . Across a three-week window, send about 60% of that, so roughly 144 points, into event token stages and leave about 96 points for dailies and materials .
Do not drain your sanity potions in week one. In practice the token surplus shows up mid-event and the shortfall always lands in the last two days .
Arknights base changes and the rest of October
Recycle Station and Activity Room
The October 9 update added a Recycle Station and an Activity Room to the base . Rebalance your room budget: start with two Recycle Stations, expand once output is stable, and do not strip everything at once.
A museum event later in October
Later in October there is a limited-time Museum of Appearances evolution event, with themed scenes as the main rewards; check the official site for exact dates . Keep some tokens in reserve rather than spending everything at once.More Arknights coverage at gghubs.com guides.
Arknights FAQ
Do I have to pull Clementha?
A: Not necessarily. She takes 50% of the six-star rate and needs team support; if your Guard lane is fine, save the pulls .
Is Core Tactician really free?
A: Yes. She is the five-star Specialist-Alchemist given away by the event, so she costs nothing and is worth building .
When does Yesterday Sea end?
A: Stages and the exchange shop close on 2026-10-30 at 03:59, and login rewards cannot be back-filled.
How should I split daily sanity?
A: Roughly 240 points a day, split 60/40: about 144 points to event stages and about 96 to dailies .
What do I buy first?
A: Limited tokens and event furniture first, since they never return; Lungmen Dollars last .
Arknights action list
- Claim the daily login rewards before you farm, every single day.
- Buy in this order: limited tokens, module materials, generic materials, Lungmen Dollars.
- Split sanity 60/40, roughly 144 points to the event and 96 to dailies.
- Hold sanity potions for the final two days.
- Add two Recycle Stations first, then reshuffle base shifts.
Game Guides
- Palworld 1.0.5 Breeding and Base Guide: Passives, Ranch and Work Splits
Palworld 1.0.5 guide covering the breeding power rules and special combos, how to filter mutated passive skills, which Pals belong on the ranch, how to reshuffle base Work Suitability after Ancient Bark dropped to level one, and the v1.0.4 Pal Critic exchange changes and build cap.
- Reverse: 1999 4.0 Dongzhi Team Guide: Lineups and Red Arrow Build Order
Reverse: 1999 4.0 guide covering how the Dongzhi system actually runs and why execution matters, Red Arrow's level and Psychube build order, which Insight upgrades to take first, three Dongzhi lineups, the execution mistakes that cost turns, and the free pulls in the 4.0 cruise celebration.
- Love and Deepspace Core Farming Route: Hunts, Stamina and Shop Priority
Love and Deepspace progression guide covering the three Core Hunt zones and their open days, difficulty thresholds, the daily and weekly activity gift boxes, exchange priority at the Heart Sand shop and the interstellar market, and which spare cores to dismantle.
- Honkai Star Rail 4.6 Pearl Build Guide: Relics, Light Cone and Elation Teams
Honkai Star Rail 4.6 guide covering Pearl as an Elation sustain unit, her mitigation and action-advance mechanics, relic sets and stat targets, why her signature light cone's energy matters, how four-Elation teams are built, speed breakpoints, and how to farm during the Planar Fission double-drop window.
- Genshin Impact 7.1 Escoffier Build and Skirk Freeze Team Guide
Genshin Impact 7.1 guide covering Escoffier as a Cryo polearm sub-DPS and healer, which of the two artifact sets to run, main and sub stat priorities, weapon options and talent costs, and how the two Skirk freeze teams split their roles.
- Wuthering Waves 3.7 Xin Build Guide: Echoes, Teams and QoL Changes
Wuthering Waves 3.7 guide covering Xin as the first playable Sentinel, her dual-form kit and Resonance Liberation, Echo and substat priorities for an Electro Rectifier unit, the team preset and Echo stacking quality-of-life changes, and how to choose between Suoming and the four re-run Resonators.
- Zenless Zone Zero 3.3 Severian Build: Drive Discs and Team Preview
Zenless Zone Zero 3.3 preview covering Severian's Aero Attack role, his signature W-Engine and drive disc stat priorities, how the two banner halves split the cast, and how to settle your resources before the version ends.
- Palworld 1.0.5 Awakening Guide: Radiant Gem Farming and Holy Water Costs
Palworld 1.0.5 (2026-09-15) leaves Awakening as the only system that permanently raises a single Pal's ceiling: at an Ancient Workbench, 50 Radiant Gems of one element plus 10 World Tree Holy Water yields one Awakening Crystal, and consuming it permanently boosts that Pal's base HP, Attack and Defence. Finish the specimen first, reach level 80 and lock in the passives before spending gems .