Below I've listed a few of the top travel magazines and publications, ranked by readership [note: some not all – this is by no means an exhaustive list]. These are a good place to start if you want to delve into understanding travel publishing.
Note: stats are taken from the publication's advertising pages or from web comparison sites like similarweb.com and are correct as of January 2018.
The top travel magazines (with online stats where relevant):
Escapism: circulation 101,700 | avg 200,000 to escapismmagazine.com in last six months
Condé Nast Traveller: combined print & digital edition circulation 78,000 | avg 850,000 visits to CNtraveller.co.uk in last six months
SUITCASE magazine: circulation 68,000 | avg 88,000 visits to suitcasemag.com in last six months
National Geographic Traveller: circulation 58,000 | avg 135,000 visits to natgeotraveller.co.uk in last 6 months
Lonely Planet Traveller: circulation 42,000 | online stats listed below for lonelyplanet.com
Wanderlust: circulation 34,000 | 400,000 visits to wanderlust.co.uk
Sunday Times Travel: circulation 63,000 from July-Dec 2016
Food and Travel: circulation 31,000 | avg 41,000 visits to foodandtravel.com in last six months
National newspapers travel sections ranked by paper's popularity in print and online [source].
Daily Mail travel: reached 16.7 million people pcm from 2016-17
The Sun travel: reached 14 million people pcm from 2016-17
Guardian travel: reached 10.6 million people pcm from 2016-17
Telegraph Travel: reached 10.2 million people pcm from 2016-17
The Mirror travel: reached 9.8 million people pcm from 2016-17
The Times travel: reached 6.3 million people pcm from 2016-17
Online travel publications
A few of the top online travel publications based in the UK, and websites for US travel publications [stats from similarweb.com as of January 2018].
CNN Travel: avg 90 million monthly visits in last six months
lonelyplanet.com: avg 17 million monthly visits in last six months
Travel & Leisure: avg 6.8 million monthly visits in last six months
roughguides.com: avg 2 million monthly visits in last six months
worldtravelguide.net: avg 767,000 monthly visits in last six months
afar.com: avg 950,000 monthly visits in last six months
loveEXPLORING.com: avg 60,000 monthly visits as of July 2018
I have no doubt missed some publications in this list. If you think I've made a mistake (I am, after all, only human) or I should add anyone in, please do get in touch here.