Gemini 3.5 Pro
- Provider
- Status
- Preview
- Context
- 2,000,000 tok
Gemini 3.5 Pro is Google’s announced next flagship model, unveiled at Google I/O on 19 May 2026. Its headline features are a 2-million-token context window — the largest of any production frontier model, double the 1M on Gemini 3.5 Flash — and a built-in Deep Think reasoning mode for the hardest scientific, mathematical and coding problems (Tech Times).
It is not yet widely available. As of mid-June 2026 Gemini 3.5 Pro is in limited Vertex AI preview, with general availability expected in late June 2026 (Tech Times) — its launch slipped past I/O, with Sundar Pichai asking the audience to “give us until next month.” Official benchmarks and pricing have not been published, so much of what is known about 3.5 Pro is announced specification or expectation rather than confirmed fact; this page flags which is which. Until it ships broadly, Gemini 3.1 Pro remains Google’s GA flagship.
Quick specs
| Provider | |
| Announced | 19 May 2026 (Google I/O) |
| Status | Limited preview (GA expected late June 2026) |
| Context window | 2,000,000 tokens (announced) |
| Reasoning | Built-in Deep Think mode |
| Pricing | Not published (reports expect ~$15/$60 — unconfirmed) |
| Benchmarks | Not published as of mid-June 2026 |
| Best for | Very long-context analysis, hardest reasoning, deep multimodal work |
| Limitations | Not generally available; specs largely announced/expected, not verified |
What is known (and not) about Gemini 3.5 Pro
Google positions Gemini 3.5 Pro to absorb the use cases previously routed to its Ultra tier: the hardest reasoning tasks, deep multimodal work and very long-context analysis (Enterprise DNA). Two things are officially announced:
- A 2M-token context window — double Gemini 3.5 Flash’s 1M and the largest in any production frontier model.
- A built-in Deep Think reasoning mode — extended chain-of-thought for hard science, maths and coding, building on the Gemini 3 Deep Think approach.
Beyond that, the picture is provisional. Official benchmarks and pricing have not been released. One report cited internal data suggesting 10–15-point SWE-bench Verified gains over the 3.1 generation, but that is unverified (Tech Times); and reports expect pricing around ten times Gemini 3.5 Flash — roughly $15 input / $60 output per million tokens — but Google has not confirmed it (byteiota). Treat both as expectations, not facts.
Availability and rollout
Gemini 3.5 Pro was announced at Google I/O on 19 May 2026, but its launch slipped: as of 9 June 2026 it remained in limited Vertex AI enterprise preview, with general availability expected later in June (Tech Times). Reports indicate it will reach Google’s $20 AI Pro and $250 AI Ultra consumer plans first. Because it is not yet broadly available, our best AI models ranking lists it with “Limited” availability rather than as a model you can rely on today.
How Gemini 3.5 Pro is expected to compare
A clean, same-harness comparison is not yet possible because Google has not published benchmarks. Directionally, Gemini 3.5 Pro is expected to extend Google’s lead on context length (2M tokens) and multimodal breadth, and to challenge Claude Opus 4.8 and GPT-5.5 at the frontier — but until official numbers land, those are expectations. For verified, available models, see Gemini 3.1 Pro, Claude Opus 4.8 and GPT-5.5.
Known limitations
Not generally available. As of mid-June 2026 it is limited-preview only; most users cannot access it.
Specs are largely announced or expected. The 2M context and Deep Think mode are official; benchmarks and pricing are not, and circulating performance figures are unverified.
Expected high price. If the ~$15/$60 expectation holds, it would be among the more expensive frontier models — though again, unconfirmed.
FAQ
Is Gemini 3.5 Pro available yet?
Not widely. It was announced at Google I/O on 19 May 2026 but, as of mid-June 2026, is still in limited Vertex AI preview, with general availability expected late June 2026. Gemini 3.1 Pro is Google’s current GA flagship.
What is special about Gemini 3.5 Pro?
Two announced features stand out: a 2-million-token context window — the largest of any production frontier model — and a built-in Deep Think reasoning mode for the hardest problems.
How much will Gemini 3.5 Pro cost?
Google has not published pricing. Reports expect roughly ten times Gemini 3.5 Flash — about $15 input / $60 output per million tokens — but this is unconfirmed and should not be relied on.
How good is Gemini 3.5 Pro?
Unknown officially. Google has not released benchmarks; one unverified report suggested 10–15-point SWE-bench Verified gains over the 3.1 generation. We will add confirmed figures once Google publishes them.
Last verified 18 June 2026. Gemini 3.5 Pro is announced but not generally available; its 2M context window and Deep Think mode are official, while benchmarks and pricing are unpublished and the figures cited here are reported expectations, not confirmed facts. Confirm against Google’s official pages once it ships.