Transport Alicante to Denia

There is a direct bus service about every hour to the bus station benidorm where you have to change for the ionward leg to Denia. Find out details here www.alsa.es

As previous respondent noted, public bus company Alsa  is the cheapest. However, if you have flexibility re travel times, it is worth studying the bus timetable so that you don’t have too long a wait in Benidorm and ideally a fairly direct Benidorm to Dénia route - some take in practically every village along the way, not recommended for anyone prone to travel sickness. If there are a few of you sharing a private taxi the cost per person wasn’t too crazy in the past but I don’t have recent info re charges

Have a look at Beniconnect

Beniconnect: Alicante airport transfers, shuttle and private taxis - Beniconnect

I have seen this company marketing itself as direct to airport. Had an experience when daughter travelling with 2 yr old was being picked up close to 6 a.m. to arrive at airport around 9 - picking up other travellers in towns along the way. Before booking check what expected travel time is. Service is good if all  are opting for one of the Denia drop off points

Per the other postings and in direct answer to your question:

I actually had to do a last minute run back to the UK the other day and had no option but to try this for the first time myself.  I was impressed as it cost (from memory) a quite reasonable 18 euros (15 for the Denia to Alicante bus, 3 for the bus connection to the airport:

There is an Alsa bus from the Denia bus station and if you have flexibility look for the service that runs direct to Alicante with one short stop in Benidorm. As someone said, the other times appear to take in all stops along the way and takes ages. I wasn't looking forward to the trip but I have to say I was impressed, nice air conditioned coach with wifi etc. The bus drops you in downtown Alicante, take a quick stroll up to the Train station and outside you will see the C6 bus service to the airport. 

Pity they dont syncronise with the flight arrivals I get in to Alicante 25th at 20:00 bus leaves at 19:00 , still have to get to JP.

Ive booked a taxi €119 door to door, bargain.