When was Claude 3 Opus released?

Claude 3 Opus was released by Anthropic on Mar 4 2024.

When was Kimi K2 (0905) released?

Kimi K2 (0905) was released by Moonshot AI on Sep 5 2025.

Which is better at coding, Claude 3 Opus or Kimi K2 (0905)?

Kimi K2 (0905) leads on SWE-Bench Verified — Claude 3 Opus 33% vs Kimi K2 (0905) 65.8%.

Which scores higher on GPQA Diamond, Claude 3 Opus or Kimi K2 (0905)?

Kimi K2 (0905) leads on GPQA Diamond — Claude 3 Opus 50.4% vs Kimi K2 (0905) 75.1%.

Is Claude 3 Opus or Kimi K2 (0905) open source?

Kimi K2 (0905) is an open-source / open-weight model released by Moonshot AI. Claude 3 Opus is a proprietary model released by Anthropic.

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Claude Opus 4.8

May 28 2026

Home/Compare/Claude 3 Opus vs Kimi K2 (0905)

Claude 3 Opus vs Kimi K2 (0905)

0 vs 2 benchmarks won

	Anthropic Claude 3 Opus	Moonshot AI Kimi K2 (0905)
Overview
Company	Anthropic	Moonshot AI
Release date	Mar 4 2024	Sep 5 2025
Model type	—	—
Open source	No	Yes
Specifications
Parameters	—	1T
Context window	—	256k
Benchmarks
Coding SWE-Bench Verified	33%	65.8%Best
Science GPQA Diamond	50.4%	75.1%Best
Timeline
Release gap	Claude 3 Opus shipped 550 days before Kimi K2 (0905)

Which is better: Claude 3 Opus or Kimi K2 (0905)?

Kimi K2 (0905) leads Claude 3 Opus on 2 of the 2 benchmarks they both report (SWE-Bench Verified, GPQA Diamond). Claude 3 Opus shipped 550 days before Kimi K2 (0905), so benchmark comparisons should account for the intervening progress.

Kimi K2 (0905) is an open-source / open-weight model; Claude 3 Opus is proprietary.

On SWE-Bench Verified, Kimi K2 (0905) leads at 65.8% vs Claude 3 Opus at 33%. On GPQA Diamond, Kimi K2 (0905) leads at 75.1% vs Claude 3 Opus at 50.4%.

Frequently asked questions

When was Claude 3 Opus released?: Claude 3 Opus was released by Anthropic on Mar 4 2024.
When was Kimi K2 (0905) released?: Kimi K2 (0905) was released by Moonshot AI on Sep 5 2025.
Which is better at coding, Claude 3 Opus or Kimi K2 (0905)?: Kimi K2 (0905) leads on SWE-Bench Verified — Claude 3 Opus 33% vs Kimi K2 (0905) 65.8%.
Which scores higher on GPQA Diamond, Claude 3 Opus or Kimi K2 (0905)?: Kimi K2 (0905) leads on GPQA Diamond — Claude 3 Opus 50.4% vs Kimi K2 (0905) 75.1%.
Is Claude 3 Opus or Kimi K2 (0905) open source?: Kimi K2 (0905) is an open-source / open-weight model released by Moonshot AI. Claude 3 Opus is a proprietary model released by Anthropic.