During events, qualified players gain access to special maps, which usually pertain to specific World War 2 battles; the only exception was a tie-in to the anime Aoki Hagane no Arpeggio: Ars Nova. Event maps stay up for about two weeks and are popular for farming ships not found in normal sorties.

While sortieing in specific event maps, special Abyssal Fleet bosses may be encountered on predefined nodes.

Starting Spring 2014 event, LoS -based checks were implemented. A fleet's total or equipment LoS affects movement through the map nodes and whether you reach the boss node. Since then, this mechanic has been implemented into extra operations maps.

Event Preparation

The standard requirements to participate in an Event are:
- At least a 75% sortie win-rate. This is shown in the Fleet HQ Stats page.
- At least 5 free ship slots for new kanmusu to join before sortieing.
- At least 20 free equipment slots before sortieing.

Event Mechanics

Ship Locking

Full Article: Ship Locking

Ship locking is a system that restricts to which maps a certain ship may be sortied.

To illustrate, the Summer 2015 ship locking restrictions will be used:

BLUE Tag: E1 and E2
GREEN Tag: E3 and E6
ORANGE Tag: E4
RED Tag: E5

With the additional restriction for the final map E7:

Any EXCEPT ORANGE Tag: E7

n.b. the actual color of the tags were Yellow and Orange, but red has been used for better display

A ship that commences a sortie to a map for the first time receives a colored tag for that particular map, if applicable.
- Tags are received regardless of map difficulty setting
- Not all maps tag ships, for example, E7 did not issue a ship tag.
Any ship, regardless of tag, may sortie to a map for which easy difficulty has been chosen
- - e.g. Kongou sorties to E1, receiving a blue tag. She may then sortie to E3 (green tag) only if the difficulty setting for E3 is easy.
Ships that do not have tags may sortie to any event map, however, once they receive a tag, they are bound by the restrictions
- - e.g. Haruna has not been used yet and is untagged, she may sortie to E7 on medium difficulty. If she then sorties to E5, she will receive the orange tag, and may no longer sortie to E7

Difficulty Settings

- Difficulty settings have been implemented, resulting in easier or harder enemies with lesser or greater rewards. Difficulties also sometimes ship drops as well as drop rates. When dealing with ship locking, sometimes the 'Easy' difficulty will allow already-locked ships, although doing maps on easy will still put the stamp on new ships.
Combined Fleet mechanics are often implemented on some maps during events.
- Limited-time quests are sometimes required to unlock the next map.

Stockpile Creation

A stockpile of resources & buckets will be required.
- Given a stockpile under the resource softcap, the natural regeneration rate of resources is 10,800 fuel, ammo, and steel per week, and 3600 bauxite.
  - For reference, expedition 5 being run non-stop will bring in a gross 27,000 fuel and ammo per week, and 1800 steel and bauxite
- Buckets do not naturally regenerate, and may be attained from expedition 2 at an average rate of 1 bucket per hour
  - In practical gameplay, Fuel (used for repairs and sorties) is much more important than Ammunition (only for sortie), while steel is the least important resource (only for repairs),
  - Bauxite usage varies greatly depending on the current demands of the fleet (a carrier or LBAS-dependent event will consume bauxite rapidly, while less CV-heavy events will consume far less)

Although it's also a general rule-of-thumb, it deserves extra mention here: always have at least two of each ship type ready & leveled as the event maps' fleet composition requirements will not be known beforehand.
- However, ship locking has made this even more important. Though on Easy Difficulties (see above) ship locking is not enforced, it can cut down on possible rewards from clearing maps; not having a well-spread fleet can reduce effectiveness throughout the event!
- Remember to plan for possible combined fleet actions as well: Having several leveled standard carriers and light carriers are important for Carrier task forces; having high-level battleships and cruisers is important for surface task forces; and Heavy Cruisers, Torpedo Cruisers, Destroyers and a Light Cruiser are needed for the escort force.