"It haunts me," he admits, and he's not the only Liverpool player that day to make such a revelation since that day. "It all happened right behind my goal. I can see those images today, if I think about it. They will never leave. It doesn't get removed from your mind. I will never forget."
Due to the new inquest into events that day, Grobbelaar's account of what he saw at Hillsborough are unable to be reported due to legal reasons, but he recalls what the players went through after they returned to the changing room.
"Kenny [Dalglish, the manager] said: 'Keep yourself warm we might be going back out.' We didn't know the extent of what had happened," the 56-year-old explained.
"Then one of our fans burst into our dressing room. We knew him. He broke down in front of us. He said he had seen 10 bodies carted off already. He said it was like a warzone. Kenny ushered him out because he didn't want to upset the players.
"Then the referee told us the game had been abandoned. From there it was just a sombre mood."
The squad showered and boarded the coach to head back to Anfield.
"Nobody said anything.
"For two hours on the journey back home we just listened to the radio. Every 10, 15 minutes we would hear an update - 20 deaths, 25 deaths. When it got to 30 deaths we switched off the radio - we couldn't listen to any more."
Grobbelaar, who now lives in Canada since retiring from football in 2007 after a brief comeback with Glasshoughton Welfar, also backed the ongoing campaign for justice for the 96 that died on that fateful day.
The Zimbabwe international admitted he is still angered that the case remains unanswered, and says it is "totally wrong" that families have not had their questions answered 25 years on from the Hillsborough disaster.
"I still get angry because the answers have not been forthcoming," Grobbelaar says.
"Twenty-five years - for the families not to have had answers. That is totally wrong. Twenty-five years is a long time. Families have gone now. They never saw justice for the sons and daughters. None of us will find peace until there is an answer.
"That is what we are fighting for - we have to stand with them. They have asked the same questions but have never got the answers. They have had part-answers. They need the answers.
"Thankfully and hopefully they will get that answer. It has taken this long because they thought this would go away. But it hasn't. It never will."