Ducati convert Bautista and Haslam, who made the move from Kawasaki, ended the year tied on points, finishing ninth and 10th in the championship, while Honda was a distant fourth in the manufacturers' race.
Honda becomes the second manufacturer to officially reveal its WSBK challenger in 2021 livery after Ducati, while defending champion Kawasaki will become the third later on Tuesday.
Mercado replaces Takahashi at MIE
Honda satellite team MIE Racing has announced it will continue to field a single CBR1000RR-R in support of the factory outfit, but with a new rider in the form of WSBK veteran Leandro Mercado.
Argentinian rider Mercado makes the move from the Motocorsa Ducati team to fill the seat that was occupied in 2020 by Japanese rider Takumi Takahashi.
“I’m very glad to announce that I’m joining the MIE Racing Honda Team for the upcoming WorldSBK season," said Mercado. "It’s a new challenge for me and I will give it my all to achieve our goals.
"For the first time in my career, I will ride a Honda, an iconic brand. I’m looking forward to riding the CBR1000RR-R at the Barcelona official tests and to start working with the team. I want to say thank you to MIE Racing for putting its trust in me and to everyone that has helped make it happen."
Suzuka 8 Hour winner and All-Japan Superbike champion Takahashi struggled to make an impression last year in his first full WSBK campaign, not finishing higher than 14th.
This year Takahashi will race in British Superbike for Honda alongside compatriot Ryo Mizuno, who represented the brand in JSB last year and finished fourth in the standings, and Glenn Irwin.
The WSBK grid will maintain Japanese representation this year with the arrival of JSB champion and one-time MotoGP starter Kohta Nozane at the GRT Yamaha squad.