Google AI Mode in Search is running on a new model. Google shipped Gemini 3.8 Flash on September 2, 2026, and added it to AI Mode's model menu on the same day it released the model. Robby Stein, VP of Product for Google Search, announced the rollout on X, stating that 3.8 Flash is "available today in AI Mode for Google AI Pro & Ultra subs around the world."
What Changed in AI Mode
Google's September 2 announcement described Gemini 3.8 Flash as its third Flash release in only six weeks and its "most intelligent workhorse model," delivering significant improvements from 3.7 Flash across software engineering, agentic tasks, and critical, multi-step reasoning in specialized domains.
Gemini 3.6 Flash arrived on July 21, 2026, Gemini 3.7 Flash on August 13, and Gemini 3.8 Flash on September 2. That is a change from the 3.7 Flash rollout three weeks earlier, when Search followed a day after the initial announcement. With 3.8 Flash, AI Mode was included in the model launch itself, meaning the selectable model in AI Mode now changes on Google's model release schedule.
Users access 3.8 Flash from the "+" icon in AI Mode's "Ask anything" bar. Stein's screenshot shows it listed under "Gemini 3 models" between "Auto" and "Pro," the same section where 3.7 Flash appeared on August 14.
Model Capabilities and Benchmark Gains
Google's announcement describes 3.8 Flash as its most intelligent workhorse model, with significant improvements from 3.7 Flash across software engineering, agentic tasks, and critical, multi-step reasoning in specialized domains. On Google's published benchmark table, DeepSWE v1.1 improved from 65.3% to 73.7%, Terminal-bench 2.1 from 85.8% to 89.4%, OSWorld-2.0 from 50.6% to 59.0%, Vals Finance Agent v2 from 59.0% to 61.4%, and HLE-Verified from 53.6% to 54.9%.
The model achieves 54.9% on HLE-Verified, demonstrating multi-step reasoning across STEM, humanities, and professional fields. Google attributes these performance gains to a design choice it describes as the model working harder, executing extra reasoning steps and calling tools iteratively, and at times using more tokens to maximize performance at higher effort levels.
Pricing and Availability
Gemini 3.8 Flash is available at the same introductory price as 3.7 Flash at $0.75 per million input tokens and $3.75 per million output tokens. That introductory price expires on December 31, 2026.
For consumers, 3.8 Flash is available to Google AI Pro and Ultra subscribers across the Gemini app, AI Mode in Google Search, and Gemini in Google Sheets. Developers can access 3.8 Flash through Google Antigravity, the Gemini API via Google AI Studio and Android Studio, and Stitch. Enterprises can use Gemini Enterprise.
Alongside the main model, Google introduced Gemini 3.8 Flash Cyber, described as its most capable cybersecurity model with frontier-level performance in vulnerability detection and automated patching, available to trusted defenders through its new Fairwind Program.
What This Means for Search Marketers
The rapid Flash release cadence carries a practical implication for marketers and SEOs evaluating AI Mode behaviour: free-tier AI Mode users do not receive a model selection option and instead receive the default model, while paid subscribers can manually select 3.8 Flash from the model dropdown. Teams benchmarking AI Mode responses, including citation patterns, query interpretation, and multi-step answer quality, should note that the underlying model accessible to paying subscribers has now changed, and results recorded under 3.7 Flash may not carry over to 3.8 Flash.
Google noted in its September 2 announcement that the 3.8 Flash release marks the third Flash model in only six weeks, reinforcing that AI Mode's model layer is now updated on a compressed timeline tied directly to Google's broader model release schedule.
