Yes - you can take it in the bath or swimming with care, for up to 30 minutes.
The sensor is waterproof and you can wear it when bathing showering or swimming. It's been tested to 2.5 meters deep and for immersion up to 2 hours. Avoid taking it in water that is deeper or for longer than 2 hours.
Drying
Be careful when drying yourself because the adhesive is less effective when wet. If you notice strange readings after towelling dry, there's a chance you may have knocked the sensor a little too hard.
Don't use a hairdryer to dry the patch because the air comes out at hotter than the sensor's safe operating limit of 45 degrees celsius.