**No.** Greece uses the **euro (€, EUR)** exclusively. Canadian dollars (CAD) and US dollars (USD) are **not widely accepted** for payment in Athens or anywhere in Greece.
What to do:
Tip: Decline DCC (Dynamic Currency Conversion)—pay in **euros**, not your home currency, to avoid 3–7% markup.
No need for cash-heavy travel; cards work for 95%+ of transactions. Small tavernas, taxis, markets may prefer cash.