And the former Pompey youth player says it's a 'privilege' to complete a switch to a team he knows very well.
Oastler has put pen to paper on a two-year Hawks deal after his contract at National League South rivals Oxford City came to an end.
For the Milton-based 30-year-old, it's a move to a club he's familiar with - and where he holds the position as head of coaching of the Westleigh Park-based Havant & Waterlooville Pro:Direct Academy.
But Oastler, who had spells at QPR, Torquay United and Gosport Borough prior to his four seasons at Oxford, is adamant joining Hawks is much more than just a convenience.
The defender stressed he's joined the club to get them back in the National League, where they spent the 2018/19 season.
Portsmouth-born Oastler said: 'It’s a privilege to sign here. Me and Dos (Paul Doswell) have been speaking for a couple of weeks now and it was something ... as soon as he mentioned coming here to sign and play it turned my head.
‘To be honest, it’s the only club I would have left Oxford City for. I’ve had four great years there but this is a great opportunity for me.
‘It’s a great thing to be able to do (academy work and play for the club).
‘I coach in the academy but I’m not just signing because I coach in the academy. It’s an opportunity to carry on my career, I’m very much enjoying my coaching, but my playing side is my playing side and I’m focused on that.
‘It’s great to be able to do both jobs and hopefully we can see some of the academy prospects coming through.
'You want to be ambitious and this is a club that definitely is ambitious.
‘I think they could play probably two levels above with the training during the day and they’re trying to do things properly.'
Oastler becomes boss Doswell's second summer signing after the arrival of his former Oxford City colleague James Roberts was announced last week.
Oastler admitted with some of the new additions expected in the coming weeks, Doswell's squad will come under huge pressure to deliver promotion.
But the commanding centre-half has no doubt he and his team-mates will be able to cope with teams raising their game against them.
Oastler added: 'It’s now down to us to do the business on the pitch. What comes with Havant in the National League South is a little bit of pressure.
‘Pressure is a privilege in my eyes but there are teams who are coming to come here and want to beat Havant because they're a big team at this level.
‘We’ve got to be able to do that and I’m sure we will do with the players he (Doswell) is signing and hopefully we can have a good season.
‘You’ve got to as a footballer (relish pressure).
‘You’ve got to have the right people in the changing room, you’ve got to be able to deal with it.
‘Like I said, there are going to be teams who come here and want to beat Havant so we’ve got to be able to deal with it - I’m sure we will.'
Oastler will add competition in an era where Hawks were short in the pandemic-wrecked 2020/21 campaign.
With Moussa Diarra rejoining Woking in late January, Doswell only ended with Sam Magri and Craig Robson as contracted central defensive options.