Want the full weekly plan around this?
See the whole Play Plans & Challenges collection.
See the collectionFor the genuine few minutes you're tied up, a child can run one of four bounded, self-scoring football challenges alone in the garden.
No one needs to referee it, provided they stay in sight or earshot and it stops after ten to fifteen minutes rather than becoming the whole afternoon. I used to hover by the back door half-watching while half-arguing with a call I couldn't get off, saying "go and play" to a child who had no idea what that actually meant, until I started handing over a number to beat instead. A call, mid-recipe, or settling a sibling, whatever the reason, the same fix works.

Something to actually chase
This only works if the challenge scores itself, because a parent who is genuinely busy can't be the referee. Four solo football games with no partner needed, each with a built-in number to beat. For a longer stretch, a football scavenger hunt works on the same principle: hide the clues once, then the trail runs itself.
Fence rebound count. Stand a few steps back from a fence or wall, pass it in, count the clean returns before a miss. Beat that number next time.
Three-target tally. Three household items at different distances, one point per hit, restart whenever. The full version, with distances and scoring, lives on three item target shooting.
Silent touches streak. Dribble with no sound from foot or ball, count the streak until something taps too loud, then start again. The solo version of the silent dribbling challenge, which also has a listener variant for when someone's free to play.
Beat-your-number sprint. Set a kitchen timer for a rough time limit, one skill (keepy-ups, wall passes, target hits), try to beat whatever number came before.
What actually counts as alone
Treat ten to fifteen minutes as the outer edge for independent play football for one child, and stay in sight or within earshot the whole time. A position statement on active outdoor play found that children who are closely, constantly supervised outdoors are measurably less active than children given some independent space (Read the outdoor play position statement, 2015). This supports a nearby-but-not-hovering style of supervision as genuinely useful rather than just convenient. That statement is general, not football-specific, sets no age threshold or safe-time figure of its own, and only supports a present-but-less-hovering adult, not true out-of-sight absence, so this page's own eyesight and time guidance goes further than the citation itself claims.
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Keep a child busy alone with a football
Pick the challenge together before stepping away, mark a clear start point with a shoe or cone so there's no argument about it later, hand over a kitchen timer if it's the beat-your-number sprint, and choose a target that never needs retrieving from a road. A simple line does the handing-over: "Shall we pick your number before I go and get dinner started?" Then step back a bit and let the number do the reminding instead of you.

Self directed football game for kids
This is for the genuine gap, not most evenings, and every one of the four challenges above works just as well as a shared game once a second person is free. The fence rebound count becomes a passing count with someone returning it, the target tally becomes a shared score. The version worth protecting is still the shared one, this is only for the minutes that are genuinely not available.
Quick answers
Treat ten to fifteen minutes as the outer edge, then go and check in properly rather than letting it run indefinitely. It's a point to check in, not a number to stretch every time.
There's no fixed age that makes it automatically fine. What matters more is staying in sight or within earshot the whole time and picking a self-directed football game for kids with a fixed, safe target rather than judging by a birthday alone.
A bounded, self-scoring one: a fence rebound count, a three-target tally, a silent touches streak, or a beat-your-number sprint against a kitchen timer. Anything with a built-in number to chase works better than an open-ended "go and practise".
Keep going
Three places to go next, depending on what tonight needs.
See the whole Play Plans & Challenges collection.
See the collectionOne dependable, focus-built option.
Try silent dribblingDistances and scoring, worked through in full.
See the target gameTonight's five minutes
Agree the challenge and the number to beat, then step away for the ten minutes you actually need.