Several tour companies in Budapest will rent you bikes during your stay, with one of the largest being Yellow Zebra Tours. Additionally, Donkey Republic has a fleet of local bikes that can be rented via a phone app and left anywhere once you’ve finished using them. Budapest also has a city-operated bike rental program known as Bubi.
After purchasing a 1, 3 or 7 day access ticket, bikes can be picked up from dozens of rental racks located all over downtown Buda and Pest. Using them for less than 30 mins incurs no extra charge (and a new bike can be taken right away), with a small charge for every additional 30-min block of use.
Meanwhile, cycling in Budapest is a pleasant experience with plenty of bike lanes both in the inner city and along the riverbank and other key routes throughout the city.