The Australian conservationist broke the news Wednesday with a pic of her in her wedding dress smooching her hubby, Chandler Powell, at the Australia Zoo -- same place they engaged last summer.

As excited as she clearly is to be hitched -- Bindi said a lot of their planning, spanning nearly a year, had to be scrapped last minute because of COVID-19 ... including the size of the guest list.

She says, "We’ve planned this beautiful day for nearly a year and had to change everything, as we didn’t have guests at our wedding."

Bindi goes on ... "This was a very difficult decision but important to keep everyone safe. We wish all of our friends and family could have been there with us, however it’s lovely that we will be able to share photos and videos."

Bindi says her mom, Terri, was present ... ditto her brother, Robert. She also says they lit a candle in her dad's honor. That's about it as far as friends and loved ones go ... but it's cool, 'cause the gal ends here by spreading a pretty important message.

"Right now we’re encouraging the world to hold onto hope and love, which will carry us forward during this profound time in history."

Congrats!