At the moment, there are zero airlines flying to Tunis. Go through the results to find the right flights for you – you can adjust the filters to see find even more flights to Tunis.
If you want to broaden your search, look at flights departing from other airports.
The distance between London Heathrow to Tunis is 1833 km. You can see the various flight times in the results.
If you want to travel in March, it's best to book your flights early, as this is peak season in Tunis. The cheapest month to fly is normally December – try searching three to four months prior to then to get a bargain. You can also search by month, which will reveal the cheapest time of the week to fly.