The bus operator has previously been operating its customer service outlet from the Old Library as Central Library has been closed for refurbishment.
Opening hours at Central Library are 10am-6pm Monday – Fridays and 9am-4.30pm on Saturdays.
Cardiff Bus has also announced it will be launching a competition for its customers with concessionary passes.
A winner will be selected at random every month to win a £50 High Street gift voucher.
The vouchers can be spent in over 20,000 stores, including Argos, Boots, Debenhams, House of Fraser, River Island and Toys ‘R’ Us.
To enter, customers with concessionary passes must write their contact details on the back of their Cardiff Bus ticket and post it in the collection box at the bus operator’s customer service outlet.
One winner will be selected on the last Friday of every month.
For full terms and conditions, customers are advised to visit the Cardiff Bus website www.cardiffbus.com.
Gareth Stevens, business development manager at Cardiff Bus, said: “We’re delighted to return to Central Library following its refurbishment. It’s in the ideal location for customers to pop in and pick up any timetables for Cardiff Bus.
“We’re also excited to launch our competition. We always try to find ways to thank our customers and we are delighted to be able to run the competition. It means that people can benefit from the vouchers, which can be spent in thousands of stores in the UK.
“It’s really simple to enter, customers just need to keep hold of their tickets, write their contact details and post it in our collection box.”