According to Freedom of Information responses from local authorities, the average cost of an adult cremation has risen by just over a third.
The cost of new anti-pollution equipment and larger coffins have been blamed for the increase.
Neath Port Talbot, Rhondda Cynon Taf and Bridgend councils saw the biggest rise.
Not all councils have a crematorium under their control.
More than 170 UK local councils each run at least one crematorium.  In other areas they are operated by private firms.
The average adult cremation costs £640 in the UK, but critics say crematoria are being run inefficiently.
Bridgend - £425, up 45% to £615
Cardiff - £432, up 19% to £515
Swansea - £435, up 33% to £580
Conwy - £430, up 28% to £552
Gwynedd - £382.30, up 37% to £523
Neath Port Talbot - £385, up 52% to £585
Pembrokeshire - £439, up 28% to £564
Rhondda Cynon Taf - £420, up 49% to £626
Wrexham - £455, up 42% to £646
Cremation fees at some council-owned facilities in Wales have risen by more than 50% since 2010.