Nairobi is 1 hour ahead of Bucharest
Best overlap: 8:00 AM to 5:00 PM in Bucharest is 9:00 AM to 6:00 PM in Nairobi.
For the smoothest call, aim inside 8:00 AM to 5:00 PM in Bucharest, i.e. 9:00 AM to 6:00 PM in Nairobi. Nairobi is 1 hour ahead of Bucharest, but with 9 hours of common ground you can hold morning or afternoon meetings without anyone working odd hours. Note that Bucharest follows daylight saving while Nairobi stays put, so the times above drift by an hour seasonally.