Context :

Aims : To assess the nature of three WNh stars in the SMC , to constrain stellar evolution beyond the main sequence at low metallicity , and to investigate the metallicity dependence of the clumping properties of massive stars .

Methods : We compute atmosphere models to derive the stellar and wind properties of the three WNh targets .
A FUV/UV/optical/near-infrared analysis gives access to temperatures , luminosities , mass loss rates , terminal velocities and stellar abundances .

Results : All stars still have a large hydrogen mass fraction in their atmosphere , and show clear signs of CNO processing in their surface abundances .
One of the targets can be accounted for by normal stellar evolution .
It is a star with initial mass around 40-50 M _ { \odot } in , or close to , the core He burning phase .
The other two objects must follow a peculiar evolution , governed by fast rotation .
In particular , one object is likely evolving homogeneously due to its position blue-ward of the main sequence and its high H mass fraction .
The clumping factor of one star is found to be 0.15 \pm 0.05 .
This is comparable to values found for Galactic Wolf-Rayet stars , indicating that within the uncertainties , the clumping factor does not seem to depend on metallicity .

Conclusions :