Gemini 3.5 Pro Delayed Again as Google Works to Improve Its AI Model

Google’s highly anticipated Gemini 3.5 Pro remains unreleased after missing several expected launch windows, leaving developers and enterprise customers waiting for the company’s next major Pro-tier AI model.

Google CEO Sundar Pichai indicated at Google I/O on May 19 that the model was already being used internally and would arrive the following month. However, the June target passed without a public release.

The delay has continued through July and August, with Google yet to announce a firm public launch date for Gemini 3.5 Pro.

Gemini 3.5 Pro Misses Multiple Targets

The original plan was for Gemini 3.5 Pro to follow the launch of Gemini 3.5 Flash in June. When that did not happen, reports pointed to further development and testing.

By July, reports indicated that Google was working to improve the model, particularly its coding capabilities. Reuters, citing Bloomberg, reported that the company was months behind schedule as it worked to address performance issues.

Google later released Gemini 3.6 Flash and Gemini 3.5 Flash-Lite on July 21, while Gemini 3.5 Pro remained in testing with partners. Google’s developer changelog confirms the July release of the Flash models.

Coding Performance Reportedly a Major Focus

Coding appears to be one of the main areas receiving additional attention.

Reports have said Google was attempting to improve Gemini 3.5 Pro’s coding capabilities after the model did not meet certain internal performance expectations. 9to5Google, citing Bloomberg, reported that Google had updated training data in an attempt to improve coding performance, although the results were reportedly disappointing.

Other reports have discussed reliability concerns and changes to the model’s development. However, Google has not publicly confirmed all of the reported details surrounding the delay.

That distinction is important because the exact reasons for the continued delay remain based partly on reporting rather than a complete official explanation from Google.

Google Continues Releasing Flash Models

While Gemini 3.5 Pro remains unavailable, Google has continued adding models to its Flash lineup.

The company made Gemini 3.6 Flash and Gemini 3.5 Flash-Lite generally available in July. Google described Gemini 3.6 Flash as offering improved token efficiency and stronger coding and agentic-planning capabilities.

Google also launched Gemini 3.7 Flash in August, further expanding its offerings for coding and agent workflows. This means developers have continued receiving new Gemini models even as the expected Pro release remains pending.

Prediction Markets Reflect the Uncertainty

The uncertainty around Gemini 3.5 Pro has also been reflected in prediction markets.

As of August 24, Polymarket pricing reportedly put the probability of no new Gemini Pro release before September 30 at 69%. The figures represent the expectations of market participants rather than Google’s own forecast.

Prediction-market prices therefore provide an indication of market sentiment, but they should not be interpreted as confirmation of Google’s development schedule.

No Confirmed Launch Date

The biggest unanswered question remains when Gemini 3.5 Pro will become publicly available.

Google originally indicated a June release, but that deadline passed. Subsequent reported targets also failed to produce a public launch. As of late August, reporting still described the model as delayed, with no confirmed release date.

For developers, the situation means Google’s newer Flash models remain the publicly available alternatives while Gemini 3.5 Pro continues development and testing.

Conclusion

The delay surrounding Gemini 3.5 Pro highlights the difficulty of bringing increasingly capable AI systems to market while meeting performance and reliability expectations. Google has continued releasing other Gemini models, but its anticipated Pro-tier model remains unavailable.

Until Google provides an official launch announcement, reported release targets and explanations for the delay should be treated cautiously. For now, Gemini 3.5 Pro remains a highly anticipated but unreleased Google AI model with no confirmed public launch date.