The Garmin Forerunner 25 is not a modern smartwatch, and it was never designed to be one.
It does not offer:
- AMOLED display
- Blood oxygen monitoring
- ECG measurement
- Advanced training load analysis
- Extensive sports modes
Instead, it focuses on the features that matter most to runners:
- Reliable GPS tracking
- Accurate distance and pace recording
- Extremely lightweight design
- Long battery endurance
- Physical buttons that work in all weather conditions
The Forerunner 25 represents a different approach to wearable technology.
It is a simple training instrument rather than a smartphone replacement.
In 2026, newer Garmin models provide much more functionality, but the Forerunner 25 still has value for runners who want:
“A watch that records running data without unnecessary distractions.”
Overall rating:
7.8/10
1. Product Positioning: Garmin Forerunner 25
The Garmin Forerunner 25 was introduced in 2015 as an entry-level GPS running watch.
Its target users were:
- Beginner runners
- Recreational athletes
- 5K and 10K runners
- Half marathon trainees
- Users looking for a simple GPS training device
Unlike Garmin’s higher-end Forerunner models, the Forerunner 25 focused on essential running features.
The main purpose was:
Record the run, analyze the data, and improve training.
The watch has now been discontinued, but it remains available on the second-hand market because of its simplicity and durability.
2. Garmin Forerunner 25 Specifications
| Feature | Specification |
|---|---|
| Brand | Garmin |
| Model | Forerunner 25 |
| Release Year | 2015 |
| Category | GPS Running Watch |
| Display | Monochrome LCD |
| Resolution | 128 × 128 pixels |
| GPS | Supported |
| Water Resistance | 5 ATM |
| Weight | 31g small version / 39g large version |
| Bluetooth | Supported |
| ANT+ | Supported |
| Battery Type | Built-in lithium-ion |
| GPS Battery Life | Around 8-10 hours |
| Smart Mode Battery Life | Up to 8-10 weeks |
The official specifications show that the Forerunner 25 was designed around efficiency rather than advanced features.
3. Design and Build Quality
Lightweight Running Design
The biggest advantage of the Forerunner 25 is its weight.
The small version weighs approximately:
31 grams
The larger version weighs approximately:
39 grams
Compared with modern smartwatches such as:
- Apple Watch
- Samsung Galaxy Watch
the Forerunner 25 feels extremely light.
During long-distance running, the low weight reduces wrist fatigue.
For marathon training or daily exercise, this remains a major advantage.
Physical Button Operation
The Forerunner 25 uses four physical buttons.
This design may appear outdated, but it works very well during exercise.
Touchscreens can become unreliable because of:
- Sweat
- Rain
- Cold weather
- Gloves
Physical controls remain dependable.
For runners who train outdoors in different conditions, button operation is often more practical than touchscreen interaction.
4. Display Experience
The watch uses:
128 × 128 monochrome LCD
By modern standards, the screen is basic.
Advantages:
- Excellent sunlight visibility
- Very low power consumption
- Long lifespan
Disadvantages:
- No color display
- No maps
- Limited information presentation
- Old-fashioned appearance
The screen is optimized for viewing:
- Current pace
- Distance
- Time
- Heart rate data
It is not designed for:
- Notifications
- Media
- Smart applications
5. GPS Running Performance
GPS tracking is the main reason to buy the Forerunner 25.
The watch records:
- Distance
- Speed
- Pace
- Route
- Calories burned
For normal running activities such as:
- 5 km training
- 10 km training
- Half marathon preparation
the performance remains useful.
GPS Advantages
Compared with using a smartphone:
The Forerunner 25 provides:
- Independent GPS operation
- No need to carry a phone
- Stable running records
- Less distraction during exercise
This is especially valuable for runners who prefer a simple training experience.
GPS Limitations
Compared with modern Garmin watches:
The GPS system is older.
Possible limitations include:
- Longer satellite acquisition time
- Lower accuracy in dense urban environments
- Older positioning technology
For everyday running, however, performance remains acceptable.
6. Running Features Analysis
Pace Monitoring
The Forerunner 25 supports:
- Current pace
- Average pace
- Distance tracking
Pace information is essential for structured training.
For example:
A runner preparing for a 30-minute 5K goal can monitor whether they are maintaining the required speed.
Virtual Pacer
The watch includes Garmin’s Virtual Pacer function.
This feature helps runners compare:
- Current performance
- Target pace
It is useful for beginners learning how to control running speed.
Auto Lap
The Auto Lap function automatically records distance intervals.
This helps with:
- Interval training
- Track workouts
- Repeated distance exercises
7. Heart Rate Features
The Forerunner 25 does not include a built-in optical heart rate sensor.
Instead, some versions support:
- Garmin ANT+ chest heart rate straps
Advantages:
Chest straps usually provide more accurate heart rate measurements than early wrist-based optical sensors.
Disadvantages:
Users need additional equipment.
For serious heart rate training, a chest strap is recommended.
8. Daily Activity Tracking
The watch supports basic activity monitoring:
- Step counting
- Calories
- Activity reminders
- Sleep tracking
However, it is not a modern health smartwatch.
It does not provide:
- Blood oxygen monitoring
- ECG
- Skin temperature
- HRV analysis
Its purpose remains running, not health diagnostics.
9. Smart Features
The Forerunner 25 supports basic smartphone connection.
Functions include:
- Call notifications
- Text notifications
- Garmin Connect synchronization
However, compared with modern smartwatches, these features are very limited.
It should not be considered an Apple Watch alternative.
10. Water Resistance
The Forerunner 25 has:
5 ATM water resistance
This means it can handle everyday water exposure.
Suitable activities:
- Rain running
- Washing hands
- Daily wearing
However, it is not designed as a dedicated swimming training watch.
11. Battery Performance Review
Battery life was one of the strongest features of the Forerunner 25.
Official performance:
GPS mode:
- Small version: approximately 8 hours
- Large version: approximately 10 hours
Normal watch mode:
- Up to 8-10 weeks
Real-world usage:
A new battery can usually support:
- Several weekly runs
- Around one to two weeks between charges
depending on GPS usage.
12. Battery Aging Problems in Garmin Forerunner 25
Because the Forerunner 25 is now more than ten years old, battery degradation is the most common issue.
Typical symptoms include:
- GPS lasting only a short time
- Sudden shutdown
- Battery percentage dropping quickly
- Failure to hold charge
These problems are usually caused by lithium-ion battery aging rather than electronic failure.
Replacing the battery can significantly extend the usable life of the watch.
13. Garmin Forerunner 25 Battery Replacement Guide
The internal battery is not designed as a user-replaceable component.
However, professional repair or experienced users can replace it.
A compatible Garmin 361-00139-00 Battery can restore battery performance when the original battery has degraded.
For owners who want to continue using this lightweight GPS watch, a Forerunner 25 Battery Replacement is often more economical than buying another running watch.
14. Battery Replacement Difficulty
Replacement difficulty:
Medium to High
Estimated difficulty rating:
4/5
Reasons:
The process requires:
- Opening the rear case
- Removing small screws
- Protecting internal connectors
- Maintaining sealing performance
The watch is compact, so careful handling is necessary.
15. Garmin Forerunner 25 Battery Replacement Steps
Step 1: Turn Off the Watch
Before repair, fully power off the device.
Step 2: Remove the Rear Cover
Carefully remove the screws.
Avoid damaging:
- Rear housing
- Waterproof gasket
Step 3: Open the Internal Structure
Pay attention to:
- Ribbon cables
- Main board connections
- Battery connector
Step 4: Disconnect Old Battery
Remove the aging battery carefully.
Step 5: Install New Battery
Install the replacement battery and test:
- Power on
- Charging
- GPS connection
- Button operation
Step 6: Restore Sealing
After opening the watch, waterproof performance may decrease.
The gasket and sealing condition should be checked carefully.
16. Choosing a Replacement Battery
A correct replacement battery should match:
- Model compatibility
- Voltage requirements
- Connector type
- Physical dimensions
A suitable Garmin GPS Watch Battery allows users to continue using the original hardware without replacing the entire device.
For older Garmin watches, battery replacement is often the most practical repair option.
17. Common Garmin Forerunner 25 Problems
Battery Life Decline
Cause:
Lithium battery aging.
Solution:
Replace the internal battery.
Slow GPS Acquisition
Possible causes:
- Long storage period
- Old satellite information
Solution:
Use the watch outdoors and allow time for GPS synchronization.
Bluetooth Sync Problems
Check:
- Garmin Connect application
- Phone Bluetooth settings
- Permission settings
Button Failure
Possible cause:
Long-term exposure to:
- Sweat
- Moisture
- Dirt
Cleaning and inspection may help.
18. Advantages of Garmin Forerunner 25
Main strengths:
- Extremely lightweight
- Reliable GPS tracking
- Excellent battery endurance
- Physical buttons
- 5 ATM water resistance
- Garmin Connect ecosystem
- Independent operation without phone
- Good second-hand value
19. Disadvantages of Garmin Forerunner 25
Limitations:
- Outdated monochrome screen
- No optical heart rate sensor
- Limited smart functions
- No advanced training analysis
- No system updates
- Battery replacement requires repair skills
20. Who Should Buy Garmin Forerunner 25?
Recommended users:
- Beginner runners
- Budget-conscious athletes
- Users who only need GPS tracking
- People who dislike smartphone distractions
- Second-hand GPS watch buyers
Not recommended for:
- Advanced triathlon athletes
- Users needing navigation maps
- Health monitoring users
- Smartwatch enthusiasts
21. Garmin Forerunner 25 vs Modern GPS Watches
| Category | Garmin Forerunner 25 | Modern GPS Watches |
|---|---|---|
| GPS | Good | Excellent |
| Battery Life | Excellent | Good |
| Weight | Excellent | Good |
| Display | Basic | Advanced |
| Health Features | Limited | Extensive |
| Operation | Simple | Complex |
| Price | Very Affordable Used | Expensive |
Final Score
| Category | Score |
|---|---|
| GPS Tracking | 8.5/10 |
| Running Features | 8/10 |
| Battery Life | 9/10 |
| Comfort | 9/10 |
| Smart Features | 5.5/10 |
| Display | 5.5/10 |
| Repairability | 7/10 |
| Used Value | 8.5/10 |
Overall Rating:
7.8/10
Final Verdict: Is Garmin Forerunner 25 Still Worth Using in 2026?
The Garmin Forerunner 25 is not a smartwatch.
It is a dedicated running instrument.
It removes unnecessary features and focuses on:
- GPS accuracy
- Lightweight design
- Long battery life
- Simple operation
Modern Garmin watches are far more advanced, but they are also more complicated and expensive.
For runners who only need:
“Distance, pace, route, and reliable training records”
the Forerunner 25 remains a practical choice.
A high-quality Garmin 361-00139-00 Battery or Garmin GPS Watch Battery can extend the life of this classic GPS running watch and keep it useful for many more years.
The Garmin Forerunner 25 proves that a simple device built for one purpose can still have value long after newer technology appears.