Mistral Small 3 and o3-pro don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Mistral Small 3 shipped 160 days before o3-pro, so benchmark comparisons should account for the intervening progress.

Mistral Small 3 is open weight, while o3-pro is proprietary.

Direct benchmark comparisons are unavailable — Mistral Small 3 and o3-pro don't publish scores on any of the same benchmarks.