You will find no direct flight from Belfast to Bournemouth. Flights only arrive at Bournemouth from holiday destinations around Europe - there are no domestic flights from the British Isles. It is nonetheless possible and efficient to travel from Belfast to Bournemouth via indirect flights and rail travel.
The nearest airport to Bournemouth providing flights from domestic destinations (including Belfast) is Southampton.
Flybe offers direct one-way flights from Belfast City Airport to Southampton for less than £40 on their website, if you book in advance and are flexible with your travel dates. If your travel is short-notice, you could find yourself paying over £100, and sometimes closer to £200.
Similarly, return travel from Flybe can cost less than £80 if you book a few weeks before your travel date and are flexible with your departure time.
There are 6 flights on weekdays between Belfast and Southampton, each taking approximately 1 hour and 20 minutes. There is a slightly reduced service at weekends.
After arriving at Southampton, there is a simple rail connection from Southampton Airport to the centre of Bournemouth, which takes less than 40 minutes and can cost as little as £2 if you book in advance online on the National Rail Enquiries website.
The service is regular, operating 3 times every hour during the day. The first service is at 06:13 and the final service is at 01:36.
With effective time-planning, this could see you travelling from Belfast to Bournemouth using these flights and the aforementioned train service with a total journey time of less than 3 hours.