During events, qualified players gain access to special a time-limited world with special maps, which usually reference historical operations; the only exception was a collaboration event with the Arpeggio franchise: Aoki Hagane no Arpeggio: Ars Nova. Event maps stay up for an indeterminate amount of time, usually measured in weeks, which grew as the game progressed to be anywhere between 2 and 8 weeks.

Event maps pose considerably higher challenge levels compared to normal maps, employing exclusive special Abyssal Fleet bosses and mechanics, such as the Combined Fleet.

Current Event

Fall 2021 Event - Return of the Naval District Saury Festival
Return of the Naval District Saury Festival

Past Event List

The past events are listed below for reference.

Spring 2013 Event - Break into the Enemy Anchorage!
Break into the Enemy Anchorage!
Summer 2013 Event - Southern Waters Assault Reconnaissance!
Southern Waters Assault Reconnaissance!
Fall 2013 Event - Final Battle! Iron Bottom Straits!
Final Battle! Iron Bottom Straits!
Christmas 2013 Event - Intercept! Fleet of Fog
Intercept! Fleet of Fog
Spring 2014 Event - Recon planes, launching!
Recon planes, launching!
Summer 2014 Event - Operation AL/MI
Operation AL/MI
Fall 2014 Event - Operation Kon
Operation Kon
Winter 2015 Event - Counter-attack! Assault on Truk Anchorage
Counter-attack! Assault on Truk Anchorage
Spring 2015 Event - Order! Operation 11
Order! Operation 11
Summer 2015 Event - Counterattack! The Second Operation SN
Counterattack! The Second Operation SN
Fall 2015 Event - Breakthrough! Maritime Transport Operation
Breakthrough! Maritime Transport Operation
Winter 2016 Event - Sortie! Operation Rei-Go!
Sortie! Operation Rei-Go!
Spring 2016 Event - Deployment! Land-based Aerial Division!
Deployment! Land-based Aerial Division!
Summer 2016 Event - Counterattack! The Second Battle off Malay Peninsula
Counterattack! The Second Battle off Malay Peninsula
Fall 2016 Event - Announcement! The Third Fleet Operation Act
Announcement! The Third Fleet Operation Act
Winter 2017 Event - Reconnaissance Force Emergency Deployment! Operation "Hikari"
Reconnaissance Force Emergency Deployment! Operation "Hikari"
Spring 2017 Event - Sortie! Fifth Fleet To the North East!
Sortie! Fifth Fleet To the North East!
Summer 2017 Event - Crossing into the West Again! The European Rescue Operation!
Crossing into the West Again! The European Rescue Operation!
Fall 2017 Event - Showdown at Operation Shou-gou! Battle of Leyte Gulf (Part 1)
Showdown at Operation Shou-gou! Battle of Leyte Gulf (Part 1)
Winter 2018 Event - Showdown at Operation Shou-Gou! Battle of Leyte Gulf (Part 2)
Showdown at Operation Shou-Gou! Battle of Leyte Gulf (Part 2)
Fall 2018 Event - Set Sail! Combined Fleet, to the West
Set Sail! Combined Fleet, to the West
Winter 2019 Event - Interception! Operation Buin Defense
Interception! Operation Buin Defense
Spring 2019 Event - Commence Allied Relief! "The 2nd Hawaii Operation"
Commence Allied Relief! "The 2nd Hawaii Operation"
Summer 2019 Event - European Counterattack Operation! Commence "Operation Shingle"
European Counterattack Operation! Commence "Operation Shingle"
Fall 2019 Event - Advance! The 2nd Southern Operation
Advance! The 2nd Southern Operation
Hinamatsuri 2020 Mini-Event - Peach Festival! Offshore Waves
Peach Festival! Offshore Waves
Summer 2020 Event - Stop the Invasion! Island Defense Fortification Operation
Stop the Invasion! Island Defense Fortification Operation
Fall 2020 Event - Escort! Fleet Transport Operation
Escort! Fleet Transport Operation
Spring 2021 Event - Clash! Night Battle off Lunga
Clash! Night Battle off Lunga
Summer 2021 Event - Reinforcement Transport Operation! Battle of the Mediterranean
Clash! Night Battle off Lunga

Event Preparation

Full Article: Help:Event Preparation

Participation requirements

  • Must have a 75% sortie win ratio.
  • Must have 5 empty ship slots for new ships.
  • Must have 20 free equipment slots.

Stockpiling

Accumulating a stockpile of resources (    ) and consumables (buckets  and flamethrowers ) prior to the event start or during the weeks that lead up to an event is extremely recommended.

  • Using the soft cap mechanic to your advantage might be beneficial should the situation demand it. For each resource under the soft cap, it is generated up to 1440 for     and 480 for  , per day.
    • For reference, expedition 5 being run non-stop will bring in a gross of 3850 fuel and ammo, and 257 steel and bauxite per day.
    • As buckets and flamethrowers do not regen over time, focusing on stocking them might be preferable on a higher priority. Expeditions 02, 04 & A2 for buckets and 2-1 for flamethrowers are good ways to farm with very high efficiency and low maintenance.
    • Fuel and ammo are the most used resources and also the most easily obtained resources through expeditions. Steel is used on a much smaller scale in comparison, but is substantially harder to stockpile in a shorter period of time. Bauxite uses will vary depending on each particular map.

Event Mechanics

Ship Locking

Full Article: Ship Locking

Ship locking is a system that restricts to which maps a certain ship may be sortied. When a ship is sortied to an event map for the first time, it will have a tag applied to it. The Tag System prevents any fleet with ships that have a tag different from the one that the map accepts from sortieing to said map. In Easy and Casual difficulties, tags are still applied, but are not checked, meaning you may still sortie fleets with ships with different tags, however, the map's tags will still be applied to ships without any. Ships that are already tagged cannot lose it through any means. Furthermore, a map might accept any or multiple tags, and as well not issue any tags.

Difficulty

Exclusive to event maps, a difficulty can be selected. The difficulties are referred to as "classes". Classes go from D (丁) to A (甲), with the western standard for difficulty being Casual (丁), Easy (丙), Normal (乙) and Hard (甲). Difficulty changes the enemy compositions, routing rules, and map rewards accordingly, as well as ship drops tables with both their rates and availability being affected.