Short answer: there’s no single bank that’s universally “lowest-fee” in Sri Lanka — it depends on the product and how you bank (savings vs current, required minimum balance, ATM usage, inward/outward transfers, international transactions). That said, several banks commonly advertise very low or no monthly maintenance for standard savings and have relatively low transaction fees:

• Seylan Bank — no monthly maintenance on many retail savings accounts and low minimums. (deposit.lk)
• National Savings Bank (NSB) — very low minimum deposits for basic accounts and often no monthly maintenance on ordinary savings. (deposit.lk)
• Standard Chartered Sri Lanka — some retail savings products (e.g., Marathon Saver) have no monthly maintenance (but often require higher minimum balance). (deposit.lk)
• Commercial Bank of Ceylon — publishes low monthly service-charge tiers (e.g., as low as LKR 25 for very small average balances in some schedules) and detailed tariff PDF. (combank.lk)
• State Bank of India (SBI Sri Lanka), HNB, DFCC, etc. — all publish full tariff schedules; specific charges (non‑maintenance, ATM fees, closure fees) vary by account. Examples: SBI and HNB tariff pages show the exact per-item charges and minimum‑balance penalties. (sl.statebank)

How to pick the lowest-cost option for you

• Identify your main costs: monthly maintenance (or minimum-balance penalty), ATM fees (same‑bank vs other‑bank), branch transaction fees, inward/outward SLIPS/CEFTS charges, and closure/dormant fees. (wise.com)
• Compare the banks’ published tariff/fee schedules (banks list them on their websites). I’ve cited several official tariff pages above — check the product page for the exact account you want because fees differ by account type. (combank.lk)
• If you use mostly ATMs and e-banking, prioritize banks with free same-bank ATM withdrawals and low interbank ATM fees. If you keep very small balances, pick banks that waive monthly charges for low‑balance/senior/young‑sav accounts.

If you want, I can:

• Compare fees for a specific account type (e.g., basic savings with monthly balance under LKR 5,000; or a current account used for business) across 4–6 banks and return the lowest-cost options with citations and the specific fee line items.