You’ll need your proof of vaccination card when you travel internationally to several countries. Keep your passport and vaccine card in one safe place with a combo case that holds both.
This two-pack with different colors from Miadam would work well for you and your traveling companion to easily identify which one is yours. They are waterproof, made of faux leather and come in five color combinations for $14.99. Other options include a waterproof faux leather case from Duolove that comes in 18 colors for $3.99 to $5.99.
Here are several other styles and colors to choose from, with several under $10.