Train travel from Heathrow to St Ives

Simplest is to take the Elizabeth line from Heathrow to Paddington https://www.heathrow.com/transport-and-directions/by-rail-or-train/elizabeth-line

and then a train from Paddington to St Ives https://www.gwr.com/

Thank you.

It depends what you mean by "best".

The easiest way is National Express bus at 1130 to St Erth Railway Station, arrive 2005 where you pick up the branch shuttle train to St Ives. The bus driver will handle your luggage on and off the bus.

There are also 2 overnight buses, which you don't want after a long haul flight. I'm on one of those overnight buses in 2 days time!

By train take the rail air coach to Reading Station. Broadly every 2 hours a train goes straight from Reading to St Erth (change for the shuttle to St Ives), broadly every other hour you also have to change trains at Plymouth.

The overall journey time from Heathrow to St Ives is 6 hours, so around 3 hours faster than the single daytime bus.

Potentially you could add time to your journey by taking the Elizabeth Line or Heathrow Express in the wrong direction to Paddington, then the train (which stops at Reading) from Paddington.

The train from Paddington Station tons Ives is a 5 hours ride. Taking a National Coach is a 10 hours, big difference.

I think that folks are replying after such a short question as if the directions needed are to St Ives near the tip of Cornwall.

If it turns out that in fact the question is about St Ives near me, an exquisitely beautiful market town on the river Great Ouse in Huntingdonshire in Cambridgeshire, I can help with directions to there.