Worsley, formerly with London Irish, made his Test England debut in this year's Six Nations Championship match against Italy and joins on a three-year contract.
Taumalolo – capped 26 times – has been plying his trade with Bridgend in recent years as a strong-running fullback or centre and joins Quins on a two-year contract.
As expected, the club also announced that Ireland and Lions hooker Keith Wood and England winger Dan Luger will be leaving the club at the end of the season.
Luger will be heading for France, having signed a contract with ambitious Heineken Cup Finalists Perpignan, while Wood's future remains in the balance given his well-documented battles against injury this season.
In addition to Worsley and Taumalolo, Quins have secured the services of Irish quartet Gavin Duffy (Connacht), Andy Dunne, Ben Willis and Simon Keogh (all Leinster).
Quins have re-signed a number of players with hooker Tani Fuga clinching a three-year deal, and forwards Jon Dawson, Ceri Jones and James Hayter all committing for a further two years.
Ins:Mike WorsleySiua (Josh) TaumaloloGavin DuffyBen WillisAndy DunneSimon Keogh (Leinster)
Outs:Keith WoodMatthew PowellDavid SlemenAlex MockfordDarryl GriffinBruce StarrDan LugerBen GollingsAlex CodlingNathan Williams