The Economic Community of West African States (ECOWAS) has agreed to activate a "standby force" as a last resort to restore democracy in Niger after generals toppled and detained Bazoum on July 26.
But it says it favors dialogue to defuse the crisis.
A plane carrying the delegation landed in the capital Niamey at around 1:00 pm (12:00 GMT), a day after the bloc's military chiefs said they were ready to intervene to reinstate Bazoum.
Niger's governing military council confirmed the arrival of the ECOWAS representatives, headed by former Nigerian leader Abdulsalami Abubakar.
A previous ECOWAS delegation led by Abubakar earlier this month tried and failed to meet Bazoum and the coup leader, General Abdourahamane Tiani.
A source close to the latest delegation said it would send "a message of firmness" to the army officers and meet Bazoum.
ECOWAS defense chiefs met this week in the Ghanaian capital Accra to fine-tune details of a potential military operation to restore Bazoum if ongoing negotiations with coup leaders fail.
"We are ready to go any time the order is given," Abdel-Fatau Musah, an ECOWAS commissioner for political affairs and security said on Friday after the military chiefs' meeting. "The D-Day is also decided."
ECOWAS leaders say they have to act after Niger became the fourth West African nation since 2020 to suffer a coup, following Mali, Guinea and Burkina Faso.
The Sahel region is struggling with growing jihadist insurgencies linked to Al-Qaeda* and the Islamic State group*. Frustration over the violence has in part prompted the military takeovers.
ECOWAS troops have intervened in other emergencies since 1990, including civil wars in Liberia and Sierra Leone. Ivory Coast, Benin and Nigeria are expected to contribute troops to a Niger mission.
* Terrorist organizations banned in Russia and many other countries