I suspect the answer is probably not...

I thought I should ask before I buy another converter. I have a Waterman Phileas on the way that was sold without a converter. I have several spare Parker slide and twist converters. I'm just wondering if I can use one of them in the new pen.

If not then I should purchase a Waterman converter to arrive around the same time.

No, they will not fit.

Thanks for answering. I didn't have a Waterman here to try and I thought asking would save time. I want to use the pen as soon as it gets here