Swindells, who can play at hooker and loose forward, and another hooker in Sadler have learned their rugby league trade in Hemel Hempstead.
Coach Troy Perkins said: “Gareth is a local lad who has come through our junior system, he has been in the first team squad for the past seven seasons. He deserves an opportunity at this level.
“Tom is a good addition to the squad. He is a local junior and spent several seasons down at Broncos in the academy. He has a great attitude to training and is always keen to learn.”
Hemel play their first pre-season friendly against London Broncos‘ Under 19s on Sunday 27th January.