Apple's Worldwide Developers Conference kicks off June 8, bringing a fresh batch of software updates across the company's ecosystem, including WatchOS 27 for the Apple Watch. This year, however, all eyes are on Siri. After years of falling behind rivals, Apple's voice assistant is reportedly set for its biggest overhaul yet, with new AI capabilities and deeper integrations expected to take center stage at WWDC.

With Siri's glow-up dominating the headlines, the WatchOS 27 update, which we expect to be iterative, will likely get buried. But that's not necessarily a bad thing if what Apple is really building isn't just a smarter assistant, but a smarter coach.

Last year was a big one for WatchOS. What was sequentially supposed to be WatchOS 12 became WatchOS 26 as part of a broader rebrand that unified Apple's software naming across the board. The Apple Watch got the same Liquid Glass visual overhaul as the rest of the lineup, battery improvements and a new Apple Intelligence-powered Workout Buddy feature that delivers personalized encouragement in your ear during workouts.

For runners like me, that means hearing things like, "This is your fastest mile yet," at exactly the moment your legs are threatening to give out.

This year, by contrast, WatchOS 27 is shaping up to be more of a refinement release rather than a complete overhaul. According to Bloomberg's Mark Gurman, Apple is working on improvements to heart-rate tracking and battery. He also mentioned the Modular Ultra watch face could finally arrive on standard Apple Watch models, bringing one of the Ultra's most requested features to the broader lineup. It's basically the watch face for people who want every available pixel occupied by useful information. And if the Siri overhaul arrives as expected, it's safe to assume some of its newfound intelligence would trickle down to the wrist. 

Having spent time with Google's Gemini AI on wearables, I'd welcome the ability to get a direct answer from Siri instead of being handed a web link I'm never going to open on a tiny screen. But what I actually want from WatchOS 27, aside from better battery life, has more to do with what I don't want.

From buddy to coach

To be blunt, I don't want another subscription-based chatbot buried inside the Health app.

AI health coaches have exploded across devices and software platforms. Oura has Advisor, Whoop has Coach and Google is pushing Gemini-powered coaching through its revamping the Fitbit app into Google Health. They all analyze your health data, identify trends and package the results into something actionable. They also come at a premium and rely on your phone as the middleman between you and those insights.

Apple's answer was supposed to be Project Mulberry, a rumored health app revamp first uncovered by Gurman with its own AI-powered health coach that was reportedly designed to analyze your data and provide personalized recommendations. But his latest reports suggest the initiative has been delayed and scaled back, with pieces of it expected to arrive in the Health app later this year instead of as a standalone service. That might be a good move. 

Because if Mulberry ultimately becomes another chatbot living behind a subscription paywall in the Health app, Apple will be fighting the same battle everyone else is already fighting.

The problem isn't that Apple doesn't have an AI health coach -- it's that everyone else already does, and they're not as life-changing as they promise. 

Google's Gemini-based Health Coach can build me a solid training plan when my readiness score says I can handle the push. But once the workout starts, I'm on my own. Apple has a chance to do something different.

Imagine getting real-time feedback in your ear: how hard to push during a HIIT interval, whether your heart rate is trending too high for today's recovery load and whether your pace is slipping behind your personal best.

Apple is uniquely positioned to pull this off. The company has spent years building Fitness Plus, a video-based workout subscription service centered around real trainers, on the idea that great coaching can change the way people train. It took that philosophy a step further with Workout Buddy by training its voice on those same Fitness Plus coaches rather than a generic assistant. Apple already has the watch collecting biometric data, the AirPods sitting in your ears and the coaching expertise built into its own fitness platform.

That's a completely different category of health coach than a chatbot living inside an app. It would also require the level of in-the-moment peak heart rate accuracy the Apple Watch is known for. The rumored heart rate tracking improvements in WatchOS 27 would fit neatly into that vision.

A smarter Siri-powered assistant could give Workout Buddy the contextual awareness it needs to evolve from an encouragement engine into a genuine coaching system that uses your biometric data in real time, knows when to speak up through your AirPods (or other Bluetooth headsets) and helps you make better decisions while the workout is actually happening. The chatbot in the app could surface long-term trends, but Buddy would be the real selling point.

The one caveat is privacy. Apple has earned trust by tightly controlling health data, and any Gemini integration will naturally raise questions about what data stays local and what doesn't. Apple says requests will run through Private Cloud Compute, but understanding what you're agreeing to will be important, especially if AI becomes more deeply embedded in health features.

The Apple Watch has a battery problem

A great coach is only as good as the data behind it, and a lot of the data that determines how hard you should push yourself on any given day gets collected while you're asleep. Recovery metrics, sleep quality, resting heart rate, overnight heart rate variability, temperature fluctuations… They're the foundation for many of the readiness scores and training recommendations that these health platforms rely on.

And that's where the Apple Watch still struggles. If I forget to wear my watch to bed because it's charging, which happens more often than I'd like to admit, then there's only so much data an AI coach has to work with the next morning. Even the smartest, most accurate coaching system in the world can't fill in gaps.

With the rise of screenless health trackers like the Fitbit Air, Oura Ring and Whoop Band, consumers are getting used to wearables that stay on their wrists for a week without a charge. It's also the primary reason serious athletes reach for a dedicated Garmin over an Apple Watch for daily recovery tracking. One missed night can skew your baselines, and the Apple Watch's 24-hour ceiling presents a real limitation for the overnight data that guides recovery and training.

Software optimizations can help at the margins, but they aren't going to bridge that gap completely.

The solution, which is not coming anytime soon, would likely have to be a screenless Apple Watch companion: a band or a ring that handles overnight tracking and passive health monitoring while the Apple Watch handles the daily grind. And while we're not expecting an Apple ring at WWDC this year, there might be some clues. 

The question for WatchOS 27 isn't just whether Apple can build an AI health coach. It's whether it can build one that people will actually listen to, because it's in the right place, it collects the right data and ultimately helps you change your habits.