Not too thick, which is a good thing.  Very comfortable.  I love the colour.  The thing that I have found is that comfortable sunbrella cushions are more prone to collecting water after a rain storm.  You can easily squeeze the water out and they do not deform the cushions.  We now keep these under the umbrella or in the pool shed, if it is going to be a big rain storm.  

The very thick cushions we have bought are not as comfortable as these but the thick ones do not get as wet.