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"Give us until next month."

That is what Sundar Pichai told the audience at Google I/O on May 19, 2026. A month later, as June draws to a close — Gemini 3.5 Pro has still not launched.

As of June 25, prediction markets put the odds of a release before June 30 at around 50–55%. Google's spokesperson "declined to comment" when asked about the revised schedule.

So what is happening — and what should you do about it?

Why Gemini 3.5 Pro Matters
The Real Reasons Behind the Delay
The Best Alternatives Available Right Now
Wait vs. Start Now: Which Strategy Is Right for You?
EdTech and Business Perspective

1. Why Gemini 3.5 Pro Matters

A 2M-token context window and Deep Think reasoning — these are the two game-changers.

Key confirmed specs for Gemini 3.5 Pro:

Feature	Details
Context Window	2,000,000 tokens (2× current Gemini 3.5 Flash)
Reasoning Mode	Deep Think (internal chain-of-thought before output)
Multimodality	Frontier-level text, image, audio, and video understanding
API Pricing	Expected above Gemini 3.1 Pro at $2/$ 12 per 1M tokens

A 2M-token context window means you can process an entire 500-page textbook, a full year of meeting notes, or a large codebase in a single conversation. Deep Think targets Claude Mythos 5 and OpenAI o-series performance levels on hard math, science, and complex reasoning.

Gemini 3.5 Pro Spec Comparison

2. The Real Reasons Behind the Delay

Google chose to get it right over getting it out fast.

There is no official explanation, but analysts point to three likely causes:

① Additional safety and alignment testing Claude Fable 5 and Mythos 5 shipping in early June raised the industry safety bar. Google appears to have extended internal testing accordingly.

② Incorporating Vertex enterprise preview feedback Gemini 3.5 Pro is already in limited Vertex AI preview for select enterprise customers. Google may be incorporating their feedback before general availability.

③ Infrastructure scaling for 2M-token GA Serving a 2M-token context window at GA scale requires significant infrastructure investment. Google may be finalizing capacity before opening the floodgates.

Note: the reported July delay is still unconfirmed. By the time you read this, the model may already be live.

3. The Best Alternatives Available Right Now

You do not need to stop while you wait.

Gemini 3.5 Flash (Available Now)

The faster, cheaper sibling of Gemini 3.5 Pro — already powerful enough for the majority of tasks. Powers NotebookLM and other Google services. Better speed and cost than Pro will be.

NotebookLM (Gemini 3.5-Powered)

The June 8 update upgraded NotebookLM to run on Gemini 3.5. For research and analysis, you can already experience Gemini 3.5 capabilities through NotebookLM today.

Claude Fable 5

Anthropic's June 9 release supports a 1M-token context window and up to 128k output tokens per request. Currently one of the strongest publicly available models for complex reasoning and long-context tasks.

Gemini 3.1 Ultra

Already supports 2M-token context. If you need massive context right now, 3.1 Ultra is the practical option — though at higher cost than 3.5 Pro will likely be.

4. Wait vs. Start Now

The right answer depends entirely on what you are building.

Wait for Gemini 3.5 Pro if:

Your project's core requirement is a 2M-token context window
Deep Think reasoning will meaningfully change your output quality
You need deep integration with Google Workspace or Google Cloud

Start now with what is available if:

You are building a prototype or MVP
Current models already handle your workload
Market timing matters more than peak model capability

"Waiting for the perfect tool while the market moves on is usually a worse outcome than starting with the best available option today."

5. EdTech and Business Perspective

For education, a 2M-token context window opens very concrete possibilities:

Full textbook analysis: Feed an entire semester's worth of material and ask for a concept map or study guide in one shot.

Long-term learning history: Include months of a student's learning data in context to generate truly personalized feedback.

Curriculum benchmarking at scale: Compare national curricula side by side to identify gaps and design optimal learning sequences.

These possibilities make waiting worthwhile. But the gap between those who experiment with current tools now and those who wait until the "best" tool arrives is larger than it looks.

Wrap-Up

The Gemini 3.5 Pro delay is disappointing. But it may also be a signal that Google is choosing precision over speed — especially as competitors raise the quality bar.

Either way, the more important question is not when the tool arrives, but how fast you can build the skills to use it when it does.

Further Reading

Sources:

Gemini 3.5 Pro Missed Its June Launch — Why It's Delayed and What to Use Now

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