Key Features

Real Time Speech Feedback
Swim Activity Tracking
GPS Navigation*
Bluetooth Technology

Platysens Marlin is a Swim Meter designed to tell you your swim performance through voicefeedback using a bone conduction headset. Your pace is reported to you as you swim with no disruption to your swim stroke. In open water swims, your swim performance is captured with GPS. In the pool, motion sensors are used when there is no GPS reception. After your swim, you can connect Marlin to your phone with Bluetooth to review your data and update configurations.  

What is in the box?

  • 1 Main Unit 
  • 1 Bone Conduction Headset 
  • 1 USB to 3.5mm Audio Charging Cable
  • No more looking at your watch
  • Just press start button and SWIM
  • Hear your swim activity data as you swim
  • Lightweight and Rechargeable
  •  [Bone Conduction] is the conduction of SOUND to the inner ear through the bones of the skull
  • Optimized for speech playback underwater
  • No more earplugs falling off
  • Clips on your goggle straps


Marlin can be set to open water mode or pool mode. In pool mode, performance data is captured with the help of the motion sensors. In open water mode, performance data and navigation is enabled with the help of the GPS module. Both modes feature instant audio feedback. The metrics calculated for each mode are shown below.   


  • Time or Distance Split from Fixed Distance 
  • Total distance and time
  • Navigation with offcourse warning
  • Distance from next waypoint


  • Lap count 
  • Lap time
  • Stroke rate 
  • Total swim time 

Technical Specifications

IPX8 (1.5m)
Rechargeable Battery
Lithium Polymer (5 hours Open Water Mode*/ 10 hours Pool Mode)

Bluetooth Low Energy for low power synchronization

Bone Conduction
Speech optimized earpiece uses bone conduction for clear audio feedback under water

Main Unit (61.5mm x 39mm x 18.5mm) Weight (27g)

Global Positioning System module provides accurate tracking and navigation for open water mode*

Frequently asked Questions

What is open water mode?

Only available in the Marlin, the open water mode improves accuracy of the device with the help of GPS satellite data. Offcourse warning and navigation is provided based on predetermined waypoints and parameters set in Marlin by the smartphone application prior to your swim.

Can Marlin playback MP3s?

No, while we love our music, the Marlin is a device focused on delivering performance information.

What language does Marlin support?

Currently, we only support English as we use a speech chip where data is stored in Flash memory.

What is the difference between the Marlin-P and the Marlin?

The Marlin-P is designed for indoor pool use and does not contain a Global Positioning System (GPS) module. It can only be set to pool mode. The Marlin has the all the features of Marlin-P plus an open water mode which uses the GPS for navigation and distance calculation when used outdoors. The Marlin is yellow-green and while the Marlin-P is blue.

Does it use a rechargeable battery? What is the expected battery life?

The Marlin uses a rechargeable lithium-polymer battery. For Marlin, the battery lasts about 5 hours before recharge is needed. For Marlin-P, it lasts around 10 hours since it does not contain a GPS unit. Please note that actual usage details may affect this estimation.

How does the offcourse warning work?

Waypoints and the swim path tolerances are set in the App prior to the swim. An ideal rectangular path is created for between each waypoint. Whenever a swimmer is located outside of the path, navigation cues will be issued to guide the swimmer back to the next waypoint.  A clock notation is used to indicate the adjustments needed for the correct direction.

Is Marlin waterproof?

Marlin is waterproof to IPX8 with submersion for 1.5 m for 30 minutes. It is not designed for diving applications.

How does Marlin attach to the swimbands of your googles?

Marlin uses a simple mechanical hook that should fit most googles. If it does not fit,we recommend placing Marlin underneath your swimcap.

Can the Marlin be used in official competition?

While current rules may not have specific rules for audio equipment for swimming, we believe it is just a matter of time before all competitions will ban it because of the competitive advantage it offers. We envision there may be competitions that allow it provided all participants have equal access to Marlin. As a training tool, Marlin can help you improve your sighting. When you wear it during practise, you will learn to get a better feel of your direction because of the instant feedback it provides. You will also get a better idea of your optimal performance when you can swim in a straight line. In official competition , even though you may not be able to use the navigation feature, you can still detach the headset and use it to track your path for review after the competition.

Marlin Technical Support Information

For technical support information, please access the Marlin User Guide or Technical Support Website.

Please note the color and finish of the final product may be different from what is shown. the production version which may look different than our prototypes.  
* GPS and navigation features are NOT available on the Marlin-P