The style of some watch bands allows the wearer to adjust the size by placing the buckle into a different hole of the watch band. However, other watch bands have to be sized correctly by either adding links to make the band longer, or removing links to make the band shorter. Unless you have the proper tools at home, take your watch to a professional to have the band correctly resized. The jeweler or watch shop may perform the service for free or may charge a small fee.
Contact a local jeweler in your area. Stores that sell watches and other jewelry have the tools to add or remove watch links from the band. Explain that you would like the band to be either larger or smaller.
Contact the manufacturer. If the watch is under warranty or if you prefer to deal directly with the manufacturer, go to the company's website for information on repairs and for contact details. Follow the instructions as to how and where the watch should be shipped. For example, aside from the address, the manufacturer might ask you to measure your wrist, package the watch in a specific way or insure the watch when shipping.
Purchase a watch resizing kit. There are generic watch resizing kits on the market that allow you to resize various makes and models of watches. On the label, the kit will detail the watches it properly resizes. After opening the kit, follow the instructions for the type of watch you are trying to resize.