Eurorail Doesn't Sell London–Paris Tickets; It Sells Passes

Eurorail (now Eurail) offers rail passes (Global Pass, Select Pass) for multi-country, multi-day travel. It does not sell point-to-point tickets like London–Paris. For a single Eurostar trip:

• Book direct at eurostar.com.
• Or via Trainline, Omio, Rail Europe.
• Fares: ~£40–£200+ depending on advance, class, flexibility.

If you plan extensive European train travel, a Eurail Pass may save money; otherwise, buy the specific Eurostar ticket.