The two were picked up in northern Mali at the weekend, two weeks after the March 13 gun and grenade assault on three hotels and a beach in Grand-Bassam that killed 19 people.
The arrests were welcomed by Ivory Coast which hailed "international cooperation in the fight against terror".
The Grand-Bassam rampage, the first of its kind in the Ivory Coast, was claimed by Al-Qaeda in the Islamic Maghreb which has also carried out similar assaults on tourist hot spots in Mali and Burkina Faso.
So far, 15 people have been arrested over the Grand-Bassam attacks, with Ivorian investigators backed by anti-terror specialists and judicial expert from Paris.
The United States and Germany are also helping with the probe.
The latest suspects were identified as Ibrahim Ould Mohamed, who was arrested on Friday night, and Midy Ag Sodack Dicko, who was picked up a day later.
"Evidence suggests that they actively participated in the Grand-Bassam attack," a Malian security source told AFP, with the information confirmed by several other sources.
Ould Mohamed, who was arrested late on Friday in Goundam, 80 kilometers (50 miles) southwest of the historic city of Timbuktu, is considered a close confidante of Kounta Dallah, the suspected attacks mastermind.
"He is the driver and the right-hand man of Kounta Dallah, the brains behind the attack. He has provided some interesting information," a Timbuktu police official told AFP, without giving further details.
Dallah, who is still at large, is suspected of both organizing and taking part in the attack, according to the Abidjan prosecutor, who did not give his nationality.
"Ibrahim Ould Mohamed did not hide the fact that he is close to Kounta. He knows many things," said a source close to the Timbuktu government.
The second suspect, Ag Sodack Dicko, was arrested on Saturday in Gossi, 160 kilometers (100 miles) west of Gao, the biggest town in northern Mali, a local police source said.
He had "acknowledged that several of those involved in the operation in Grand-Bassam stayed at his place in Abidjan," the source said, referring to Ivory Coast's main city.
"He said he didn't know they were going to carry out this crimes," the source said, dismissing the claim as a bluff.