Predictive modelling of a number of ELMy H-mode JET plasmas with a trace tritium puffing was done using a combination of transport codes JETTO and SANCO. The main aim of this analysis was to study the tritium particle transport and to compare it with the neo-classical one. Previous study of deuterium transport in JET ELMy H-mode [1] showed, that at least the convective velocity was of the order of the neoclassical ware pinch for H mode plasmas. It follows from the neo-classical theory that both the diffusion coefficient and the convective velocity of trace tritium ions should increase with Zeff and with the main ion density. This should lead to a faster propagation of trace tritium towards plasma centre, which translates into a shorter time to peak in the measured neutron yield for these plasmas if transport is indeed neo-classical. The experimental evidence gives the opposite trend with a longer time to peak for high-density plasmas both with and without additional Argon gas puff.