Dice Swimming Race Game: Rules, Stroke Chart and Odds
Dice swimming is a 100 metre race on paper for two to eight swimmers. The pool is 25 metres long, so the race is four lengths, and every roll of two dice is a burst of strokes. The twist is the wall: you have to stop at the end of each length and push off again, and the race is won by the swimmer who touches the final wall first. You need two dice and a pencil, and a race takes about ten minutes. Below are the rules, the stroke chart and the exact odds.
What you need
- Two six-sided dice, or a dice roller set to two dice.
- A pool drawn on paper: one lane for each swimmer, 5 squares long, with a wall at each end. Each square is 5 metres.
- A counter for each swimmer and a tally mark for each finished length.
- Two to eight swimmers, and a random name picker to give out the lanes.
Who gets which lane?
Put every swimmer’s name into a random name picker and draw them one by one. The first name drawn takes lane 1, the second lane 2, and so on, and swimmers take their turns in lane order. Every lane is the same and every roll works the same way, so the draw just sets the lanes fairly.
How to play
- All swimmers start at the wall at one end of their lane.
- On your turn, roll both dice, add them up and look at the stroke chart below. Move your counter that many squares along the lane.
- The wall: when you reach the end of a length, stop at the wall. Any squares left over are lost, just as a real swimmer has to touch the wall before turning.
- The turn: on your next roll after a wall, push off and add 1 square to whatever you roll. Then swim back the other way.
- The finish: the race is four lengths. When a swimmer touches the wall at the end of the fourth length, the others still take their turns in that round. If several swimmers touch in the same round, the one whose touching roll had the highest dice total wins. If those totals are equal too, it is a dead heat and they share the win.
Real races are timed to a hundredth of a second, and even so swimmers have shared gold medals in dead heats. Short-course races are swum in 25 metre pools, which is why there are four lengths here. The chart is a simple home version, not an official game, so agree on it before the start.
The stroke chart and the chance of each roll
In the table, “Roll” is the total of the two dice, “The stroke” is what happens and how far you move, and “Chance” is the exact probability out of the 36 ways two dice can land.
| Roll | The stroke | Chance |
|---|---|---|
| 2 | Swallow water: no move | 1 in 36 |
| 3, 4, 5 or 6 | Steady stroke: 1 square | 14 in 36 |
| 7, 8 or 9 | Strong stroke: 2 squares | 15 in 36 |
| 10, 11 or 12 | Racing stroke: 3 squares | 6 in 36 |
A strong stroke is the most likely result, because 7 is the most common total of two dice, as explained in our guide to dice probability. A swimmer moves about 1.7 squares per roll on average, so each 5-square length usually takes three rolls, and the push off after every wall saves a little time.
How long is a race?
A swimmer needs about 11 rolls on average to swim the four lengths. The fastest possible race is 8 rolls, two rolls per length. In the next table, “A swimmer finishes in” is the number of rolls one swimmer needs to touch the final wall, and “Chance” is how likely that is, rounded.
| A swimmer finishes in | Chance |
|---|---|
| 9 rolls or fewer | about 12% |
| 10 or 11 rolls | about 51% |
| 12 rolls | about 21% |
| 13 rolls or more | about 16% |
With two swimmers, both touch the wall in the same round about 20% of the time, so the “highest touching roll” rule matters often. A true dead heat happens in about 3% of two-swimmer races. Every swimmer has the same chance to win. These numbers are worked out exactly from the rules, not simulated.
Tips
- Give each swimmer a stroke to “swim”: freestyle, backstroke, breaststroke or butterfly.
- Let one player be the starter and say “Take your marks” before the first roll.
- For a longer race, swim eight lengths, 200 metres.
- Hold heats and a final when there are more than eight swimmers.
Classroom ideas
- Measurement: each square is 5 metres. How far has a swimmer gone after two lengths and three squares?
- Probability: why is a racing stroke rarer than a strong stroke? Count the ways two dice can make 10, 11 or 12, and the ways they can make 7, 8 or 9.
- Averages: pupils count the rolls they needed and compare with the average of about 11.
- Data: make a tally chart of how many rolls each race took for the whole class.
Variations
- Relay: teams of four swim one length each, and the team that touches first after four lengths wins.
- Fast start: before the race, each swimmer rolls one die. A 6 is a great dive and starts on square 1.
- False start: in top-level swimming a false start means disqualification. For a gentle home version, a swimmer who rolls a 1 on the start die waits one turn before diving in.
- Long course: use a 50 metre pool of 10 squares and swim two lengths.
If you like races played with dice, try the dice rowing race or the dice cycling race next.
FAQ
How do you play a swimming race with dice?
Each roll of two dice moves you along a 5-square lane: 2 is no move, 3 to 6 is 1 square, 7 to 9 is 2 squares and 10 to 12 is 3 squares. Stop at each wall, push off with 1 extra square, and swim four lengths.
How long does a race take?
About 11 rolls per swimmer, and half of all races take 10 or 11 rolls.
What happens at the wall?
You stop at the wall and lose any squares left over. On the next roll you push off and add 1 square.
Does the lane matter?
No. Every lane is the same and every swimmer finishes the round, so the lane only sets the turn order.
What if two swimmers touch together?
The swimmer whose touching roll had the higher dice total wins. If those are equal, it is a dead heat and they share the win.
How many players can play?
Two to eight swimmers, one per lane. Bigger groups can swim heats and a final, or relays.