Williams, Australian football's longest-serving player, will feature in her final match on home soil when the Matildas take on China at Accor Stadium on Monday.
After a 1-1 draw with China in the first of their two-game series on Friday in Adelaide, the Matildas will be going full-throttle to give Williams a stirring farewell as they prepare for the Olympics.
The experienced campaigner will hang up the gloves after the Paris Games, which start in late July, bringing an end to a distinguished career in green and gold.
Williams has featured in five World Cups, six AFC women's Asian Cups - including the 2010 title triumph - and two Olympic Games.
The 35-year-old Melbourne Victory goalkeeper is viewing Monday night's match as a "closing of the circle".
Goalkeeper Lydia Williams has had a distinguished career both domestically and with the Matildas. (Darren Pateman/AAP PHOTOS)
"You don't really get much time as an athlete to have hindsight," Williams said on Sunday.
"You have to move on from tournament to tournament, from club season to club season.
"Over the last few months, I've been able to have that recollection and reflection on my career.
"It's definitely going to be really emotional. I'm just really excited to share one more final moment (with the team) on the pitch.
"We've known each other since we were 16 and we were those kids trying to look up for a role model.
"All of a sudden, we've become that role model."
After more than 100 appearances for her country across almost two decades, Williams says the decision to retire came naturally.
West Ham United star Mackenzie Arnold has become the preferred goalkeeper under coach Tony Gustavsson, as Williams grew into a mentoring role for rising stars such as Teagan Micah and Jada Whyman.
"It's been a process of a couple of years," she said.
"My body definitely was finding it a bit hard to back up, and credit to Mac (Arnold), obviously she's been in great form, Teagan too.
"Realising that and knowing that you had to change your mindset into what your role was turning into (was a challenge).
"Throughout that process, it was a lot of internal dialogue, but I never felt any disrespect, only support from Tony.
"Now being able to be sent off on home soil - that was really important for him (Gustavsson) to make that decision. It could have been in a completely different way."
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