The Quick Verdict
Honestly? These two together is the setup. The S70 for course strategy and full-round context, the Z30 for pin-precise yardage when it actually matters. At $649 for the watch and $229 for the rangefinder, that's a real chunk of money — but the Z30 has a Range Relay feature that sends its laser measurement directly to your S70, so you get both numbers on your wrist without pulling out a separate device. These aren't competing products. They're built to work together.
What They Actually Do
The S70 is a golf GPS watch — it maps every hole, tracks your shots automatically, and gives you distance to the front, center, and back of the green plus hazard yardages, all on your wrist. The Z30 is a laser rangefinder — you point it at the flag, press a button, and get the exact distance. Both are legal in tournament play with slope disabled. Both live in the Garmin Golf ecosystem.
The Real Tradeoffs
Precision vs. convenience
The Z30 locks onto the pin to within ±1 meter. The S70 gives you front/center/back of the green, which is usually accurate to within a few yards of a fixed point. For a 175-yard approach shot where the pin's tucked in the back-left corner, those 10–12 yards between front and back of the green matter. The Z30 tells you exactly what you're facing. The S70 tells you the range — the Z30 tells you the number.
For everything that isn't an approach shot, the S70 wins on speed and usefulness. Tee shots, layup distances, carry over water — you glance at your wrist and you have it.
Speed of use
Standing over a tee shot with a group behind you? You've already seen the hazard yardages and carry distances before you walked up. That's the watch. Rangefinder means pulling it out, finding the flag through the scope, pressing the button, reading the display, and putting it back. Fine when you have time. Annoying when you don't.
The good news with this particular pair: Range Relay. The Z30 can transmit its laser measurement to the S70, so you range it once and the number shows up on your wrist. You don't have to squint at two different screens.
What you see before you hit
This is a category-level difference a rangefinder can never close. The S70 shows you the whole hole — where the bunkers are, how far to carry the water, where the fairway narrows, the shape of the green. You're standing on a tee box you've never played, 395-yard par 4 with a fairway bunker at 245 down the right side. The S70 tells you exactly how far that bunker carries and where you need to land. The Z30 can't help you here — there's no flag to point at.
On the flip side, the Z30 can range a tree branch hanging over the fairway 220 yards out, or a bunker lip you need to carry on a blind approach. The S70 can't do that.
Information depth
The S70 is loaded: hole maps, green contours (with Garmin Golf membership), virtual caddie with AI club recommendations based on wind and your shot history, automatic shot tracking, strokes gained analysis, a barometer for plays-like yardage. The Z30 does one thing — measures distance to whatever you're pointing at. But it does that one thing better than the watch does.
Cost of ownership
S70 is $649.99. Z30 is $229. Combined: ~$879. The Garmin Golf membership is $9.99/month or $99.99/year — green contours and the full virtual caddie features are locked behind that. The Z30 runs on a CR2 battery that lasts up to a year. No subscription, no charging.
If you're buying just one: the Z30 at $229 is a much smaller commitment than the S70 at $650.
Tournament legality
Both have tournament modes. Slope has to be disabled on the Z30 — there's a mode indicator for that. The S70 has a tournament mode toggle as well.
Battery
The S70 gets 15 hours in GPS mode — enough for most rounds, but you'll be charging it every couple of days if you're playing regularly. The Z30's CR2 battery lasts up to a year. This is one maintenance difference worth knowing if you're bad about charging devices.
Who Should Get Which
Get the S70 if you want an all-in-one device that handles course strategy, shot tracking, scoring, and daily wearability. If you play new courses regularly, want the AI caddie making club suggestions, or just don't want to carry another device, the watch is the more versatile buy.
Get the Z30 if you play a handful of home courses, already know the layouts, and just want a dead-accurate distance to the pin on approach shots. Simple, reliable, no charging. At $229, it's a lower barrier to entry.
Get both if you're serious about your game and want the complete picture. The course management from the S70 plus the pin precision from the Z30 — and with Range Relay, they're genuinely integrated. A lot of single-digit handicaps run exactly this setup.
The Bottom Line
The S70 does more things. The Z30 does its one thing better. But because of Range Relay and the shared Garmin Golf ecosystem, they're more useful together than they are separately. If budget is the constraint, start with the Z30 — it's the cheaper entry and fills the biggest gap. If you're already sold on a GPS watch, the Z30 at $229 is a logical add.
Get both. The S70 on your wrist, the Z30 in your pocket.