National Cat Day? No? International Cat Day? What's that? When's that? On August 8 every year? Meowmuh says there's lots of ways to celebrate International Cat Day -- also called World Cat Day. You can volunteer at a shelter, you can visit a Cat Cafe, you can donate to a Cat Charity, adopt a stray cat, buy some cat toys/merchandise, dress up as a cat or -- bestest yet, give your own cat/s some love, affection, attention & play-time.