Forex, short for foreign exchange, is the trading of currencies against each other. Because financial centres in different countries take turns, the market stays open nonstop through the working week. Each region has a main session, and those sessions shape how easily you can buy and sell and how wide the gap between prices becomes. Understanding them helps you judge when the market is busy, when it is quiet, and why prices behave differently at different times.
Why trading sessions exist
Each major financial centre opens and closes at its own local time. When activity in a region slows, another region starts to pick up, and trading passes along. Each of these periods is called a session. Sessions follow the business day in each region, so the same currency pair can look very different depending on when you watch it.
The main sessions
The Asian session opens the trading day. It is led by markets in the east, and activity in currencies linked to that part of the world tends to be most visible during it.
The European session follows. Many of the largest currency dealers are based in the region, so trading volume usually rises as the session gets going. Movements in the euro and the pound often stand out during this period.
The North American session comes next and is shaped by large markets in that region. Economic news released there can move prices sharply, and the dollar often takes centre stage. This session tends to be busiest when it overlaps with the European session.
Where sessions overlap
Sessions overlap when neighbouring regions are open at the same time. The Asian and European sessions share only a brief window, while the European and North American sessions share a longer stretch. Overlaps are when the most participants are active and the largest volumes change hands.
Think of an overlap as a busy junction where roads meet. Traffic is heavier there, and prices can react sharply to news from both regions at once.
How liquidity and spreads change
Liquidity means how easily an asset can be bought or sold without moving its price much. In forex, liquidity tends to be highest during busy overlaps and lower when only a single region is open. Spreads, the gap between the buy and sell price, usually move the other way. When liquidity thins, the gap tends to widen, and when liquidity is deep it tends to narrow.
Quieter periods can also bring sudden jumps in price. With fewer orders in the market, a single trade can move a currency further than it would during a busy session. For how the spread works on a widely traded pair, see the glossary entry on the EURUSD spread.
How to plan around sessions
Start by deciding which sessions match the currency pairs you are interested in. A pair built around the euro tends to be most active during the European session, while a pair tied to the dollar often moves most during the North American session. Watching these patterns over several weeks helps you build a clear picture.
Next, check the economic calendar for scheduled news in each region. Releases from central banks and statistics agencies often change liquidity and spreads for a short time. Many people choose to avoid trading around those moments, or to be more careful about how much they put at stake when they do.
Finally, compare the spreads and order handling each broker offers during the sessions you plan to use, rather than relying on a single example. Each broker's own published terms set out how its pricing works, and those terms differ between providers.
Limits and common mistakes
Session times are a rough guide, not a fixed rule. Daylight saving changes, public holidays and local working hours all shift when activity picks up. Confirm the timing for each region against a current market calendar before you rely on it.
A common mistake is treating a session as a sure sign of movement. Quiet sessions can still produce sharp moves, and busy sessions can stay calm. Another mistake is assuming that a pattern seen last month will repeat exactly.
Some traders focus on a single currency pair and forget how other pairs move. Others trade during thin periods because the screen looks busy. Both habits can lead to larger losses than expected.
Next steps for timing your forex trades
Start with the guide to choosing a forex broker, which explains what to compare and how to read a broker's own terms.
Next, compare forex brokers that focus on spreads and note how each sets out its spreads and order handling. Each broker's own terms, and your local financial authority, show which trading rules cover your account.
Finally, write down which sessions cover the pairs you plan to follow, and how spreads change during each. Review that list every few months, since session timing can shift.