And with the Blues now out of the running for a RaboDirect PRO12 play-off spot, the 36-year-old has just one more appearance in Cardiff before retirement beckons.
"There will be mixed emotions on Sunday. I have been here 13 years, since 1999, so it will be a sad day to finally hang up my boots," said Williams ahead of the clash with Edinburgh at the Cardiff City Stadium in the Blues look to bounce back from five successive defeats.
"But we still have to concentrate on the game and we really need a win after the last few weeks.
"I've had some great highlights. The season we went to the Heineken Cup semi-finals was fantastic. We won in Gloucester with 14 men, then won in Biarritz and beat Toulouse in the quarter-final.
"The following year we beat Toulon in Marseille to win the Amlin Challenge Cup which was an unbelievable achievement. That all saw us rise to fourth in the ERC rankings.
"It's a shame we didn't go on to win the big one with the Heineken Cup which was something we all felt capable of doing."
Williams will be one of 12 Blues players waving goodbye to the capital crowd when he makes his 143rd appearance for the region on Sunday.
Fellow Welsh internationals Gethin Jenkins, Richie Rees, John Yapp and Rhys Thomas are all leaving the Blues this summer, while Deiniol Jones has been forced to retire with a shoulder injury.
Ben Blair, Dan parks, Maama Molitika, Paul Tito, Casey Laulalaand Fa'ao Filise are also departing and the Blues plan to hold a special shirt presentation at the end of the Edinburgh game to honour their commitment to the region.
But while Sunday will see a show of respect for the old guard, Williams is convinced that the Blues still have a bright future ahead of them despite the recent negative media coverage and a poor run of results.
"There are a lot of boys leaving, which obviously has been well documented, but there's still a lot of great players here to kick on for the future," added Williams.
"I can assure you that when you've got the likes of Sam Warburton, Leigh Halfpenny, Jamie Roberts and Bradley Davies here next year they'll be fine. A lot of European teams would bite their arms off to get those players."