Gather bamboo strips or a bamboo mat, ruler, pencil, saw or heavy scissors, sandpaper, wood glue, clamp, and a sealant
Measure and mark coaster size, usually 3.5 to 4 inches square or round
Cut bamboo into equal-length strips or circles
Arrange the pieces into the desired coaster shape
Apply wood glue to the contact points
Press the pieces together firmly
Clamp the coaster until the glue dries
Trim any uneven edges
Sand all surfaces and edges until smooth
Apply a waterproof sealant or food-safe finish
Let the finish dry completely
Add cork or felt backing if desired
Repeat to make a full set of coasters