Mailbox
Last updated 2026-09-11
The Mailbox is a system in Honkai Impact 3rd which allows the Captain to receive attachments, messages, and rewards for events and updates. All mail will contain a title, the sender, message, date sent, expiry date, and reward(s).
Overview
As of Version 4.4, all mail can be sorted, filtered, and quick-deleted. In Version 6.4, the function to Save certain mails was added alongside a filter for them. Mail can also be filtered by Collection, which includes Birthday mail. All mail can be claimed via the [Quick Claim] button. Meanwhile, the [Quick Delete] button will delete all read mail except for Saved mails, Collection mails, or mails with rewards.
The Mailbox can store 200 mails with attachments. Once this limit is reached, the oldest mail will be deleted automatically. This does not apply to mails that have been Saved.
Birthdays
Certain playable characters may send Captains mail during their Birthdays, possibly giving them certain lore, cutscenes, etc. Any mail sent for a character's birthday can only be claimed by logging in on the specific day of that character and will not show up in the mail otherwise.
In all character birthday mail, Captains can receive 
Crystals ×120, 
Asterite ×1,000, and a special birthday item. Captains can also enter their birthdate in their profile to receive a [Birthday Bonus] mail with Crystals ×100 and a 
Handmade Birthday Cake when they log in on that day. Any mail obtained from birthdays will not be quick-deleted and cannot expire.