AWS S3 offers different types of storage classes you can choose from, first let's understand the difference between Durability and Availability.

Durability and Availability

Durability: A system that is durable is able to perform its responsibilities over time, even when unexpected events may occur.

Availability: A system that is available is capable of delivering the designed functionality at a given point in time. Highly available systems are those that can withstand some measure of degradation while still remaining available.

from Well-Architected Concepts

To put it simply, Durability measures the (un)likelihood of data loss while Availability refers to the ability to access/retrieve your stored data.

When choosing what type and option, Ask yourself:

how critical is your data?

how reproducibile is it?

how often is the data going to be retrieved?

Objects stored in S3 have a eleven nines of durability (99.9999999%) - likelihood of loosing data is very rare because S3 copies objects across multiple AZ within the region.

Availability can range from 99.5% to 99.99% depending on the Storage Class.

storage classes

Available Storage Classes:

S3 Standard: low latency / frequent access

S3 Intelligent Tiering: monitors access patterns and automatically moves objects that have not been accessed to lower-cost access tiers.

S3 Standard Infrequent Access: infrequent access

S3 Standard 1 ZONE IA: infrequent access, slightly less availability because data is stored on a single AZ

On top of S3 Standard there is S3 Glacier that is a solution where we refer to to as Vaults, rather than Buckets, to better express the type of storage/access provided.

There is not Graphical User Interface and Data is not immidiately accessible, but retrieving it can take up to few hours depending on Retrieval Options (Expedite,Standard, Bulk) and type:

S3 Glacier:

S3 Glacier Deep Archive