The Quick Verdict
Honestly? The best setup here is both — the S70 on your wrist for course strategy and the Z30 in your bag for the exact pin number. They're built to work together, and Garmin's Range Relay feature means the Z30 can send its laser measurement directly to your watch. That's not something you get from mixing brands.
Buying just one? Go with the S70. At $650 versus $500, it's more expensive, but it does far more of the job across a full round — and on the courses and holes where you don't have a specific target to point at, the Z30 gives you nothing. The watch does something useful on every single shot. The rangefinder doesn't.
What They Actually Do
The S70 is a GPS golf watch: preloaded with 43,000+ courses, it shows you full hole maps, hazard layouts, and front/center/back yardages on your wrist throughout the round. The Z30 is a laser rangefinder: point it at the flag, press the button, get the distance to within a meter. Both are legal in tournament play with slope disabled. Both live inside the Garmin Golf ecosystem.
The Real Tradeoffs
Precision vs. good-enough
The Z30 measures exactly what you point at — the flag, the bunker lip, a tree you're laying up short of. ±1 meter to a specific target. The S70 gives you front/center/back of the green, which might be a 3-5 yard spread around where the pin actually is. For a 180-yard approach where the pin is cut tight to the front edge, that difference is one full club. The Z30 wins on approach shots. It's not close.
But here's the thing: most shots in a round aren't approach shots. Tee shots, layups, hazard carries — you're not targeting the pin, you're targeting a zone. The watch handles all of that faster and with more information.
Speed of use
On a busy course with a group behind you, the S70 wins on time. You glance at your wrist. Done. The Z30 means pulling it from your pocket or the cart magnet, locating the flag in the optic, pressing the button, reading the display, putting it away. That's 10-15 seconds per shot. Not a dealbreaker, but over 18 holes it adds up.
What you can see before you pull the trigger
Standing on a tee box you've never played — say, a 390-yard par 4 with water running down the left side — the S70 shows you the whole hole. The carry to clear the water. Where the fairway pinches. How far the bunker on the right starts. You can plan your shot before you ever pull a club.
The Z30 can't help you there. There's no flag on the tee box to point at. It's a measurement tool, not a navigation tool. That's a category-level limitation, not a flaw in the Z30 specifically.
Course information depth
The S70 packs in features the Z30 literally cannot have: green contours (with a Garmin Golf membership at $99.99/yr), PlaysLike distance adjusted for elevation via a built-in barometer, live wind data pulled to the device, a Virtual Caddie that factors all of it together and suggests a club, and AutoShot tracking that builds your swing history over time. Strokes Gained data after the round. The Z30 gives you one number per trigger pull, every time, nothing more.
That's not a knock on the Z30 — that one number is the most accurate distance information available. But if you want to understand your game beyond "how far to the flag," the watch is doing work the rangefinder never will.
Range Relay: the reason they're better together
This is the same-brand advantage worth knowing: the Z30 has Range Relay, which sends its laser measurement to the S70 on your wrist. So you take your Z30 reading, and it shows up on your watch alongside all the other hole data. You're not toggling between two separate devices mentally — the rangefinder feeds the watch. That integration doesn't exist if you pair either product with a different brand.
Battery and maintenance
The Z30 runs on a single CR2 battery rated up to a year. You change it once a season and forget about it. The S70 gets 15 hours in GPS mode — roughly 3-4 rounds — before it needs a USB-C charge. If you play a lot, you're plugging it in weekly. Neither is a problem if you build it into your routine, but the Z30 wins on "set it and forget it."
Tournament legality
Both are legal. The S70 has a tournament mode that disables slope. The Z30 has a verified slope-disable switch for tournament rounds. No issues with either.
Who Should Get Which
Get the S70 if you play a wide variety of courses, want shot tracking and post-round analytics, or want one device that handles everything from tee to green without pulling anything out of your pocket. It's also genuinely useful off the course — notifications, heart rate, sleep tracking, music, contactless payments. The Z30 is a golf-only device that lives in your bag.
Get the Z30 if you already have a GPS watch or a phone-based GPS solution and what you actually want is better pin precision on approach shots. Or if you play the same courses regularly and don't need hole mapping — you just want the exact number before you hit.
Get both if you're serious enough about course management that you want the full picture on every hole and the exact number on every approach. This is the setup a lot of mid-to-low handicap players actually use, and with Range Relay pushing the Z30's readings to the S70, it functions as a single integrated system rather than two separate gadgets.
The Bottom Line
These two are genuinely complementary — the S70 runs your round, the Z30 sharpens your approach shots, and Range Relay ties them together in a way that only works within the Garmin ecosystem. If you're going to buy one, pick the S70. It earns its keep on every hole, not just the ones where you're dialing in a pin.