The primary reason why swimming goggles leak is because they don't fit properly. The proper fit will provide a seal that keeps out water. However, even if the goggles are a proper fit, they still won't keep water out if you don't put them on correctly. Thankfully, finding a proper fit and then putting them on the right way isn't a difficult process.
Choose a pair of goggles that are labeled as "adult size" if you are an adult and "child size" if you are a child.
Press the goggles to your eyes, but don't put the strap around your head. If the goggles create a seal and hold tight to your skin for a few seconds without holding them in place, then they are likely a good fit. Each time you put on your goggles, remember to press them to your face. This creates a good seal.
Put the strap around your head. It should be even with the goggles and tight enough that the goggles don't slip down your nose. If it feels like the goggles are poking into your skin, you need to loosen the strap.
Pinch the nose area of the goggles to tighten that area if it feels loose. If that area feels too tight, wedge a finger under each side of the nose piece and pull. This will widen the nose area. It may take a few tries to get the nose piece comfortable for your face.
