For almost 20 years a tiny band of CIA operatives has circumvented normal travel channels to slip quietly to work at agency headquarters in Northern Virginia.

The agents, wearing backpacks and waterproof boots, left their cars or bicycles by the roadside on MacArthur Boulevard, walked boldly through the woods to a footbridge over the C&O Canal and took a hand-drawn ferry across a Potomac slough to Sycamore Island.

There they launched canoes and paddled across the river in the early morning light. They chained the canoes to trees on the other side, concealed their paddles, reshouldered their backpacks and marched up a wooded hillside, arriving at the agency's Langley gates each day just before 8 a.m.

Their unique commuting plan never had the agency's imprimatur. In fact, as the founder of the plan recalls, it was frowned upon by CIA brass as the outset.

But times have changed, said John Seabury Thomson, and the CIA is a little more open these days. No one frowns on the canoe commuters anymore.

More's the pity, because now that the canoe pool has finally earned a little respect, it's collapsing.

"We've lost the canoe pool," Thomson said the other day with an edge of urgency in his voice.

Thomson no longer uses the canoes to commute himself, having retired from the agency in 1975. But the commuters' alternatives he helped create has been adopted by a half-dozen younger CIA men and women. They have enjoyed the early runs across the Potomac and the evening trips back for the last 10 years.

Now a dark force has robbed them of their pleasure.

Someone is stealing the CIA canoe pool's canoes.

Bob Sinclair is the canoe pool leader now. On Friday, he and Thomson made what they expect will be the last CIA canoe commuter run.

"We've lost two boats in the last five months," Sinclair said after he arrived on the Maryland side of the river at 7 a.m., on schedule. "Last week someone cut the chain and took the last boat. There just isn't anything we can do. We have to leave them on the Virginia shore all day, and anyone who wants to can spend as long as he wants to figure out how to take them away.

"You can't afford to keep losing $400 boats, one after another," he added.

So the CIA canoe pool is shutting down, leaving three regulars and three more occasional boaters searching for a more traditional way to get to work.

For Sinclair, who lives in Bethesda, it's the difference between a four-mile and a 20-mile commute.

His standard procedure has been to bicycle to MacArthur Boulevard, then walk to the canoe, which means to the only fuel he uses is his own. Now he'll have to buy a motorbike or a car or "start scrounging rides," he said. "My wife thinks I ought to build an aerial tramway over the river."

In any case, he and his current colleagues, who wished to remain anonymous because there are covert angles to their jobs, will lose more than a cheap way to get to work when they join the Beltway brigades.

Before Thomson and Sinclair launched their final run, they scared up a pair of wood ducks which leaped from the water 15 yards away. Their 10-minute paddle across the river was placid and uneventful.

On the Virginia side, they walked through barren wood, but Sinclair's practiced eye picked up the earliest signs of spring-bluebells and squirrel corn starting to blossom, the first hint of life on toothworths.

They hauled the canoe up the Virginia bank and followed an old National Capital Park trail up the hillside to the George Washington Parkway, then followed the stream of cars to the CIA gate.

"Better cover up your camera," said Sinclair as he neared the entrance. "You'll give the guards a fit." Then he disappeared into the crowd, his orange backpack bobbing along as he joined the throngs piling into work.

Thomson hiked down the hill to take the canoe back to the Maryland side for good.

The CIA canoe pool was a year-round arrangement, and Thomson recalled days when the ice was so bad that the commuters skated across. He even fell in once.

For him, the best time was in the snow.

As cars slid and crashed along the highways, Thomson remembered strolling through the pristine white woods, then paddling through the serene silence of snow on the water. CAPTION: Picture, Bob Sinclair, left, and John Thomson arrive on Virginia shore near Langley on their final run. By Angus Phillips-The Washington Post