Gemini 3 Pro Preview, identified as gemini-3-pro-preview, was shut down on March 9, 2026. Google’s release notes say that old identifier now points to gemini-3.1-pro-preview. You therefore cannot treat a current response from the legacy identifier as a new test of the original Gemini 3 Pro Preview.
The available facts establish lifecycle, not a universal quality verdict. Historical capability descriptions do not prove present availability of the original preview, and a current answer about the successor is not a review of the original Gemini 3 Pro Preview. If you are choosing a model for software development now, verify the model actually served and evaluate that successor under its own identifier.
Use a task portfolio from your codebase: a constrained design critique, a multi-file implementation, a failing test, and a code-review exercise. Hold context and acceptance checks constant. Measure correctness, project-rule adherence, unnecessary edits, successful tool use, recovery, and reviewer corrections.
Keep model and agent-system effects separate, inspect traces, and review high-risk changes. Record the successor model, integration, settings, and date so the result does not get mislabeled as Gemini 3 Pro Preview. Recheck the mapping whenever Google changes its lifecycle guidance.
Source: Google Gemini 3 Pro Preview; Gemini API Release Notes. Last checked: September 16, 2026 (documentation review; no API or model test).
