$129.00
1-year plan (device + membership)Best suited for
- Owners of small dogs and cats (Fi states the Mini is designed for smaller dogs, including dogs under 10 lbs, and cats) [mfg-pr]
- Users who prioritize a very lightweight tracker (0.56 oz) and compact dimensions (42 x 30 x 12.5 mm) [mfg-pr]
- People who want multi‑week battery life and extended uptime when using a Fi Base at home (up to 3 weeks standalone; up to 3 months with a Fi Base) [mfg-pr]
Poor fit for
- Owners who cannot or do not want to use AT&T LTE‑M connectivity — the Mini relies on LTE‑M service through Fi's partnership with AT&T [mfg-net]
- Anyone unwilling to maintain a Fi Membership — a subscription is required and LTE‑M connectivity is bundled with the Fi subscription after any included trial [amz] [mfg-net]
- Use cases that require a larger or heavier tracker — Fi presents the Mini as a very small, lightweight device intended for small pets [mfg-pr]
Pros
- Exceptionally light: 0.56 oz [mfg-pr]
- Compact footprint: 42 x 30 x 12.5 mm [mfg-pr]
- Battery life options: up to 3 weeks standalone; up to 3 months with a Fi Base at home [mfg-pr]
- GPS location plus AT&T LTE‑M cellular connectivity for real‑time tracking [mfg-net]
- USB‑C charging cable included with the device [mfg]
- Waterproof construction and lightweight polymer housing reported by the manufacturer [mfg] [mfg-pr]
- Attachment flexibility: three attachment systems that fit collars/harnesses from 3/8 in to 1 in wide
Cons
- Requires AT&T LTE‑M coverage to use cellular tracking features — Fi partners with AT&T for LTE‑M service [mfg-net]
- An ongoing Fi Membership subscription is required; LTE‑M connectivity is bundled with the Fi subscription after any included trial [amz] [mfg-net]
- Manufacturer warranty exists but the term should be verified at purchase (Fi provides the warranty) [warranty]
The number that defines the Mini is 0.56 ounces — 16 grams — in a 42 × 30 × 12.5 mm housing. Fi built it for pets at the small end: dogs under 10 lbs and cats, per the company’s own positioning, with three attachment systems covering collars and harnesses from 3/8 in to 1 in wide.
Battery comes in two profiles. Standalone, Fi lists up to three weeks per charge. Paired with a Fi Base station at home, up to three months — the base lets the tracker idle on low power the way the Series 3+‘s home modes do.
The same subscription rules as the rest of Fi’s line apply: GPS runs over AT&T’s LTE-M network, and an active Fi Membership is required for the cellular features, with LTE-M service bundled after any included trial. No LTE-M coverage, no tracking. USB-C charging is included; the housing is a waterproof, lightweight polymer.
This page reflects Fi’s product materials and launch announcement; we have not clipped one to a cat.
Safety considerations
- The device relies on AT&T LTE‑M coverage for cellular connectivity; confirm LTE‑M availability in your area for live tracking functionality [mfg-net]
- A Fi Membership subscription is required and LTE‑M connectivity is bundled with the subscription after any included trial period [amz] [mfg-net]
- Fi states the Mini is waterproof and uses a lightweight polymer housing [mfg] [mfg-pr]
- Verify the manufacturer warranty term at the time of purchase; Fi provides the warranty [warranty]
Verified specifications
- Fi
- Mini
- 42 x 30 x 12.5 mm
- 0.56 oz
- lightweight polymer housing
- Three attachment systems fit collars/harnesses from 3/8 in to 1 in wide
Sizing & compatibility
Fit depends on your dog's measurements. Measure girth (the widest part of the ribcage) and consult the manufacturer's size chart before buying — a poor fit can cause chafing or let an escape-prone dog back out of the harness.
Comparable alternatives
Related reading
Sources & research
Read our research methodology and editorial standards →
- Manufacturer Fi Mini Overview - Help Center
- Manufacturer Fi Partnership with AT&T - Help Center
- Manufacturer Fi Unveils Fi Mini - Business Wire
- Amazon API Fi Mini GPS Tracker for Dogs