# Anthropic Claude Sonnet 3.5 — deprecation status

> Yes — Claude Sonnet 3.5 is retired. Anthropic deprecated it on August 13, 2025 and shut it down on October 28, 2025; API requests to it now fail. The recommended replacement is Claude Sonnet 4.6.

The original Sonnet 3.5, from June 2024, and the model that introduced Artifacts. Anthropic later shipped a second model under the same 3.5 name, which is why anyone pinned to a date needs to check which one they meant. Retired October 2025.

## Facts

| Field | Value |
| --- | --- |
| Provider | Anthropic |
| Model id | `claude-3-5-sonnet-20240620` |
| Status | Retired |
| Released | June 20, 2024 |
| Deprecated | August 13, 2025 |
| Shutdown | October 28, 2025 (275 days ago) |
| Last verified | July 30, 2026 |

## Replacement

- **Claude Sonnet 4.6** (`claude-sonnet-4-6`) · recommended — https://modeldeprecations.dev/anthropic/claude-sonnet-4-6
  - Anthropic points both Sonnet 3.5 snapshots at the same successor, so the June/October distinction stops mattering after the migration.
  - Parameters it accepts: https://modelparams.dev/models/anthropic/claude-sonnet-4-6

```diff
- "model": "claude-3-5-sonnet-20240620"
+ "model": "claude-sonnet-4-6"
```

## FAQ

### When did Anthropic Claude Sonnet 3.5 shut down?

Anthropic Claude Sonnet 3.5 shut down on October 28, 2025. API requests to it fail from that date onward.

### What replaces Anthropic Claude Sonnet 3.5?

Anthropic recommends Claude Sonnet 4.6 (`claude-sonnet-4-6`) as the replacement for Anthropic Claude Sonnet 3.5. Anthropic points both Sonnet 3.5 snapshots at the same successor, so the June/October distinction stops mattering after the migration.

### Is Anthropic Claude Sonnet 3.5 still available?

No. Anthropic Claude Sonnet 3.5 is retired and no longer served — it was shut down on October 28, 2025. Calls to it return an error.

### How do I migrate from Anthropic Claude Sonnet 3.5 to claude-sonnet-4-6?

Swap the model id in your API call: replace "claude-3-5-sonnet-20240620" with "claude-sonnet-4-6". Anthropic points both Sonnet 3.5 snapshots at the same successor, so the June/October distinction stops mattering after the migration.

## Sources

- [Anthropic model deprecations](https://platform.claude.com/docs/en/about-claude/model-deprecations) — accessed 2026-07-30

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Canonical page: https://modeldeprecations.dev/anthropic/claude-3-5-sonnet-20240620
JSON: https://modeldeprecations.dev/api/v1/models/anthropic/claude-3-5-sonnet-20240620.json