Brooks Nader and Sister Sarah Jane Ready to Party at Bezos and Sanchez's Wedding

Brooks Nader and her younger sis Sarah Jane are open to a quick European fling this weekend ... with sources telling us they're single and ready to mingle at the Sanchezos' wedding!

Sources familiar with the event tell TMZ ... Brooks and Sarah Jane -- who's also a model, BTW -- are now in Venice for the wedding festivities. Our sources say both the ladies are single, and, they're ready to party and live it up ... Italian style!

Brooks posted a video on Snapchat today, showing her taking a water taxi to her Venetian hotel, too.

We're told Brooks will likely run into one of her exes ... not the "Dancing with the Stars" pro Gleb Savchenko, with whom she had an on-again, off-again fling for a few months last year -- but, the G.O.A.T. Tom Brady instead.

BN and TB12 had a fling a few months before she went on 'DWTS' and got together with Gleb ... unclear how they feel about each other now.

Brooks and Sarah Jane showed up Friday -- so, they didn't get caught up in the rainstorm with the rest of the guests last night -- but, they made it in before the big event obviously ... the ceremony itself which is expected to take place later today.

BTW ... Brooks isn't the only A-lister who plans on partying the days away in Venice -- 'cause sources told us the newly single Orlando Bloom plans on getting down, too.