Claude Sonnet 3
Release (see availability)First Sonnet balancing capability and speed in Claude 3.
API, free Claude and Bedrock; private preview on Vertex AI.
Anthropic · Claude Sonnet version history
Dates refer to release events, not our crawl or news publication times. Announcement, preview and availability can happen on different days. This is a curated record, not an exhaustive catalogue or a guarantee of the latest version.
Named Sonnet releases and distinct announcements checked against official launch and API release notes through October 1, 2026. Numerical gaps are not filled. Availability describes launch-day access, not current support; older models may be retired.
Sources checked through
Direction: oldest → newest · Earliest documented event · Most recent documented event
Claude Sonnet 3.5 (June)
Release (see availability)Improved coding, reasoning and vision. API notes date availability June 20; launch blog currently displays June 21.
API, Bedrock, Vertex AI, Claude web and iOS.
Official sources
Link to this eventClaude Sonnet 3.5 (October update)
Release (see availability)Updated Claude 3.5 Sonnet with stronger coding and tools; preserves the launch identity rather than informal 3.6 naming.
Model available to users; computer use separately in public beta.
Official sources
Link to this eventClaude Sonnet 3.7
Release (see availability)Hybrid reasoning with optional extended thinking.
All Claude plans, API and partner clouds; extended thinking excluded free tier.
Official sources
Link to this eventClaude Sonnet 4
Release (see availability)Improved coding, reasoning and instruction following.
Free and paid Claude, API, Bedrock and Vertex AI.
Official sources
Link to this eventClaude Sonnet 4.5
Release (see availability)Focused on coding, complex agents and computer use.
Claude apps, Claude Code and API; available everywhere at launch.
Official sources
Link to this eventClaude Sonnet 4.6
Release (see availability)Improved coding, computer use and agent planning.
Default for Free/Pro; API and partner clouds, with initial 1M context beta.
Official sources
Link to this eventClaude Sonnet 5
Release (see availability)Improved autonomous planning, tools, coding and knowledge work; same-day article correction is not a second launch.
Available everywhere; launch pricing later made permanent.
Official sources
Link to this eventClaude Sonnet 5.5
Release (see availability)Improved everyday coding and knowledge work at lower per-task cost.
All platforms including API, AWS, Google Cloud and Azure.
Official sources
Link to this event