The Portuguese rider has typically opened his seasons in the Tour of Oman or Dubai but started last year in the Vuelta a San Juan. He is up for another warm-weather start in Adelaide, where he is realistic about his expectations.
"For the first time in my career, I'll be participating in the Tour Down Under. I want to get to know this race, but I'm well aware that I will end up next to riders who are already in great shape, especially the Australians," Costa said in a press release.
"For me, this will be the beginning of a long season; it will be interesting to see the first results of our winter workouts, hopefully, we will have a good pedalling rhythm by then."
Costa will support Italian Diego Ulissi who in 2014 finished on the podium at the Tour Down Under. He missed the 2015 edition after a too-high salbutamol level led to a nine-month ban that excluded him from the early races that year. In 2016, he finished outside the top 10, but last season was fifth overall.
"As has often happened in the past, the 2018 season will also start for me in Australia, in a race where I have always encountered perfect conditions for the first competitive rides," Ulissi said.
"The competition is going to be very high calibre; the two stages with climbing arrivals will be coveted by many and will serve as a good testing ground."
The team will bring back directeur sportif Philippe Mauduit, who left Bahrain-Merida to rejoin the former Lampre riders at UAE Team Emirates.
UAE Team Emirates for Tour Down Under: Matteo Bono, Simone Consonni, Rui Costa, Roberto Ferrari, Marco Marcato, Manuele Mori and Diego Ulissi.