Gemini 3.5 Pro review: the honest state of Google's flagship

Kurnia Kharisma
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Kurnia Kharisma

Katelin Teen
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Katelin Teen

Last edited July 21, 2026

Expert Verified
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So, can you actually use Gemini 3.5 Pro?

No, and I want to be upfront about that before you spend another ten minutes hunting for a download link.

I checked the three places Google would announce it, and all three agree. The DeepMind Gemini models page still lists Gemini 3.1 Pro as the current Pro flagship, with an explicit "3.5 Pro coming soon" label sitting right next to it. The Gemini API model list has no gemini-3.5-pro entry at all, only 3.5 Flash and a 3.1 Pro preview. And the API pricing page prices 3.5 Flash and 3.1 Pro, but not 3.5 Pro.

That's three independent primary sources saying the same thing. This is the whole reason most "Gemini 3.5 Pro review" articles ranking today are hollow: they're reviewing a model nobody outside Google has run.

What Google has actually confirmed

Here's the part that is on the record, straight from Google.

The 3.5 series was announced on May 19, 2026 at Google I/O, in a post bylined by Koray Kavukcuoglu, Google DeepMind's CTO. Two things matter in that post. First, the series launched with 3.5 Flash only. Second, the exact line on the flagship: Google said it was "hard at work on 3.5 Pro," that "it's already being used internally," and that they'd "roll it out next month."

"Next month" from a May 19 post means June. It's now late July. The rollout has quietly slipped past its own window by more than a month.

Google also framed the whole 3.5 line as models "combining frontier intelligence with action," which is a fancy way of saying they're tuned for agentic workflows and coding, not just chat. That framing matters, because agentic coding is exactly the area where reporting says the flagship is struggling.

Timeline of the Gemini 3.5 Pro rollout, from the May 2026 announcement to still coming soon
Timeline of the Gemini 3.5 Pro rollout, from the May 2026 announcement to still coming soon

The only 3.5 benchmarks that exist: Gemini 3.5 Flash

Since there are no 3.5 Pro numbers, the best real anchor for what the 3.5 generation can do is 3.5 Flash, which did ship. Google claims 3.5 Flash already outperforms Gemini 3.1 Pro on several agentic and coding tests, which tells you the Pro version is meant to sit above an already-strong Flash.

The published 3.5 Flash figures from the announcement:

BenchmarkGemini 3.5 FlashWhat it measures
Terminal-Bench 2.176.2%Agentic terminal tasks
MCP Atlas83.6%Tool calling / agent protocol
CharXiv Reasoning84.2%Multimodal understanding
GDPval-AA1656 EloReal-world economic tasks

Google also says 3.5 Flash runs about 4 times faster than other frontier models on output speed, landing it in the high-intelligence, high-speed corner of the Artificial Analysis index.

Performance comparison table of Gemini, Claude, and GPT models, as taken from Google's Gemini 3.5 announcement
Performance comparison table of Gemini, Claude, and GPT models, as taken from Google's Gemini 3.5 announcement

The honest read: 3.5 Flash is genuinely fast and strong on agentic tasks, and it's the floor 3.5 Pro is expected to clear. But a Flash-tier score is not a Pro-tier review, and pretending otherwise is the trap.

Why Gemini 3.5 Pro is running so late

This is the most interesting part of the story, and the part rumor pages skip.

Reporting picked up by the community, citing Bloomberg, says Google is "months behind schedule on delivering Gemini 3.5 Pro, its most powerful flagship AI model, because the company has been taking time to try to improve its capabilities, particularly in coding." One Hacker News commenter summed up the reaction:

Hacker News

">Alphabet Inc.'s Google is months behind schedule on delivering Gemini 3.5 Pro... Seems like deepmind needs to get more internal usage"

The mood among people who followed Google's 2025 run is closer to disbelief. Google was the frontier leader not long ago, then the pace fell off a cliff:

Hacker News

"Near the end of 2025, Google was on top - best LLM (Gemini 3 Pro), best video model (Veo 3.1), and best image model (Nano Banana). They seemed unstoppable. And then, they stopped. Why?"

When you dig into what people actually complain about with the shipped Gemini models, three themes keep coming up, and they line up neatly with what Google reportedly can't yet get right in the flagship: hallucination reliability, agentic coding, and consistency over long sessions.

On hallucinations:

Hacker News

"But use Gemini? You get burned by the hallucinations Gemini casually spews out on a daily basis. You develop a habit of fact checking every single answer."

And on agentic coding, where the gap to Claude Code and Codex is widest:

Hacker News

"My sense is that the Gemini models are very capable but the Gemini CLI experience is subpar compared to Claude Code and Codex... it can get confused, fall into doom loops, and generally lose the plot."

Diagram of why Gemini 3.5 Pro is running late: coding, math reasoning, and hallucination pushing a from-scratch rebuild
Diagram of why Gemini 3.5 Pro is running late: coding, math reasoning, and hallucination pushing a from-scratch rebuild

Read charitably, the delay is Google refusing to ship a flagship that face-plants on the exact things frontier buyers care about most. That's a defensible call. It's just not the story a "here's your 3.5 Pro review" headline wants to tell.

What the rumors get wrong

If you've been reading around, you've probably seen confident claims about 3.5 Pro: a 2-million-token context window, a "Deep Think" variant, a specific July 17 launch date, exact benchmark percentages. I want to flag these clearly.

None of those are from Google. They trace to aggregator and rumor blogs, and I'm not going to launder them into facts here. A couple of specifics worth correcting: there is a Deep Think reasoning mode, but the shipped one is Gemini 3.1 Deep Think, not a 3.5 Pro variant Google has announced. And that "July 17" date came and went with no launch. Treat every hard 3.5 Pro spec you see as unverified until it appears on a Google property.

What to use right now instead

Here's the practical answer, because you probably came with a real task, not a trivia question.

The top Pro-tier model you can actually run today is Gemini 3.1 Pro, and it's no consolation prize. On Google's own published benchmarks it leads GPQA Diamond at 94.3%, Humanity's Last Exam at 44.4%, ARC-AGI-2 at 77.1%, and posts a 2887 Elo on LiveCodeBench Pro. It trades the top SWE-Bench Verified spot narrowly (80.6% vs Opus 4.6's 80.8%), so on real coding it's right in the mix with the best.

The mental model I'd use:

  • Need the strongest reasoning and coding you can get from Google today? Gemini 3.1 Pro.
  • Need cheap, fast, agentic throughput? Gemini 3.5 Flash, which is generally available and has a free tier.
  • Waiting specifically for "the most powerful flagship"? That's 3.5 Pro, and it isn't out. Don't block real work on it.
Decision map for which Gemini model to use today, with 3.5 Pro marked not out yet
Decision map for which Gemini model to use today, with 3.5 Pro marked not out yet

The developer community is asking the same buying question, and mostly landing on "not yet worth switching my whole workflow":

Hacker News

"Can we switch from Claude Code to Google yet? Benchmarks are saying: just try. But real world could be different."

Worth noting the other side too: for non-coding daily work, plenty of people already prefer Gemini's factual accuracy over the alternatives, so 3.1 Pro is a legitimate daily driver, not a placeholder.

Pricing: what a Gemini Pro model actually costs today

Since there's no 3.5 Pro price, here's the real cost of the flagship you can use, Gemini 3.1 Pro Preview, on the API. Pro is the only tier with context-length pricing at the 200k-token boundary.

TierInput ≤200kInput >200kOutput ≤200kOutput >200k
Standard$2.00$4.00$12.00$18.00
Batch$1.00$2.00$6.00$9.00
Priority$3.60$7.20$21.60$32.40

All figures per million tokens, from Google's API pricing. There's no free tier for Pro; 3.5 Flash carries one.

On the consumer side, Google renamed its plans after I/O 2026. The live Google AI plans start at $4.99/mo for Google AI Plus, $19.99/mo for Google AI Pro, and $99.99/mo rising to $199.99/mo for the two Google AI Ultra tiers, which is where the highest Gemini limits and the Deep Think mode live. When 3.5 Pro ships, it'll almost certainly slot onto these same surfaces, above 3.5 Flash.

Gemini Deep Research generating a multi-page report, as taken from Google
Gemini Deep Research generating a multi-page report, as taken from Google

My verdict

Rating a model that doesn't exist is guesswork, so I'll rate the situation instead.

Gemini 3.5 Pro is the most-hyped model you can't buy. The delay is a genuinely good sign for quality: Google is holding back a flagship rather than shipping one that hallucinates and doom-loops on agentic coding, which are the exact complaints trailing the current line. When it lands, given how strong 3.5 Flash and 3.1 Pro already are, it has a real shot at retaking the frontier lead Google let slip.

But "it'll probably be great" is not a review, and it's definitely not a reason to stall. If you need a Gemini model today, 3.1 Pro is excellent and 3.5 Flash is the value pick. If you need Gemini for a specific job like customer support, the model was never the bottleneck anyway.

Try eesel AI

If the reason you're comparing Gemini models is to put one in front of customers, here's the thing I'd save you from learning the hard way: picking a model is maybe 5% of the work. The other 95% is connecting it to your helpdesk, teaching it your past tickets and macros, and making sure it stays quiet when it isn't confident.

eesel AI handles that part. It plugs into your existing helpdesk in minutes, runs on top frontier models under the hood so you're never betting on one unreleased release date, and it simulates on your historical tickets before it ever replies, so you see the real resolution rate before a single customer is affected. You don't wait for Gemini 3.5 Pro to get a working AI support agent, you get one now.

eesel AI helpdesk dashboard overview
eesel AI helpdesk dashboard overview

Frequently Asked Questions

Is Gemini 3.5 Pro out yet?
No. As of July 2026, Gemini 3.5 Pro is announced but not released. Google's DeepMind models page still shows Gemini 3.1 Pro as the flagship with a '3.5 Pro coming soon' label, and there is no 3.5 Pro entry in the Gemini API model list. The only released 3.5-generation model is Gemini 3.5 Flash.
What is the current best Gemini Pro model I can use?
Gemini 3.1 Pro is the top Pro-tier model you can actually run today, available as a preview in the Gemini API and inside the Gemini app on paid Google AI plans. It leads several public benchmarks, so it's the real subject of any honest Gemini 3.5 Pro review until the flagship ships.
How much will Gemini 3.5 Pro cost?
Google has published no price for Gemini 3.5 Pro. The best proxy is the current flagship, Gemini 3.1 Pro Preview, at $2.00 per million input tokens and $12.00 per million output tokens on the Standard tier under 200k tokens, per Google's API pricing. Consumer access starts at $4.99/mo for Google AI Plus.
Why is Gemini 3.5 Pro delayed?
Google said at Google I/O 2026 that 3.5 Pro was being used internally and would roll out 'next month.' That window passed. Community and reporting point to coding, math reasoning, and hallucination reliability as the sticking points Google is reworking before shipping the flagship.
Should I wait for Gemini 3.5 Pro for customer support automation?
No. Waiting on a raw model release doesn't get you a working support agent. A support layer like eesel AI runs on top frontier models and simulates on your past tickets before it ever replies, so you get results now instead of betting your queue on an unreleased Gemini model.

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