Why Google Delayed the Gemini 3.5 Pro Release
Google DeepMind is now aiming for a July 17 general availability date for Gemini 3.5 Pro, a significant slip from the original timeline. The model was first promised for June 2026, when CEO Sundar Pichai told developers at Google I/O on May 19 to give the company until the following month.
Reports first surfaced in late June indicating that the launch had already slipped from June into July. The stated reason was that Google needed additional time to collect feedback from early testers and refine the model further before a wider rollout.
A Complete Rebuild, Not a Simple Delay
What makes this delay notable is the scope of the rework behind it. Rather than making incremental fixes, DeepMind reportedly abandoned the original 2.5 Pro base model entirely and started over with a new pre-training pipeline.
Performance Gaps That Triggered the Rebuild
The rebuild is said to be targeting specific weaknesses that had emerged relative to competing models, including:
- Mathematical reasoning
- SVG scene generation
- Image quality
These were reportedly areas where the original architecture fell short compared to rival systems, prompting DeepMind to conclude that the existing foundation could not keep pace with OpenAI's GPT-5.6 or Anthropic's Fable 5.
Benchmark Claims Are Circulating, But Nothing Is Confirmed
Ahead of the official release, leaked benchmark results have started to spread on social media, with some claiming the rebuilt Gemini 3.5 Pro already beats Fable 5 on frontend and visual code generation tasks. These claims are unverified, and separate leaks directly contradict them.
One example: a developer posted what was said to be a leaked LMSYS Chatbot Arena screenshot showing Gemini 3.5 Pro winning an SVG coding task against Fable 5. Another source, however, reported the opposite outcome for the same type of comparison. Neither Google nor Anthropic has made any official statement addressing pre-release benchmark comparisons of this kind.
The Competitive Pressure Behind the Timeline
The delay is landing at a moment of heightened competition across the AI industry. OpenAI has reportedly been planning to launch GPT-5.6 in early July, while Anthropic's Fable 5 has already been generally available since June 9.
Adding to the pressure, four senior researchers from the Gemini team reportedly left Google for Anthropic in late June, raising additional questions about execution inside Google's AI division during this critical stretch.
What's Available Right Now
While the general release remains pending, Gemini 3.5 Pro is currently accessible in a limited capacity through Vertex AI's enterprise preview. This preview version includes a 2-million-token context window along with a Deep Think reasoning mode for more complex queries.
It's worth noting that Google has not officially confirmed the July 17 date. At least one analysis source has cautioned that the date should still be treated as a rumor rather than a confirmed release plan.