Ali Babitu Kololo and Issa Sheck Saadi are charged with killing David Tebbutt, 58, and abducting his wife, 56-year-old Judith, from a remote Kenyan resort.
Mrs Tebbutt, from Herts, was taken away in a speedboat on 11 September and is said to be in Somalia at a pirate base.
It is not clear if the people now holding Judith Tebbutt are the same as those who kidnapped her.
Mr Kololo, who used to work on Lamu island, the remote resort where the Tebbutts were staying, says he was forced at gunpoint to lead the gang to the hotel and was not a willing accomplice.
The BBC’s East Africa correspondent, Will Ross, says the court case may shed some light on the attack itself but it is unlikely to help in the effort to secure Mrs Tebbutt’s release.
He said the latest reports indicate she is being held near Haredhere, a pirate base almost 200 miles (320 km) up the coast from the Somali capital, Mogadishu – the same area where the British couple Paul and Rachel Chandler were held hostage for more than a year.
British police have been in Kenya to help find Mrs Tebbutt.
The couple come from Bishop’s Stortford and their son Oliver lives in Watford.
Somalia has been wracked by fighting between various militias for two decades, so weapons are widely available and there are many armed groups who could be responsible.