The two-leg dash will see Merkel, at the helm of Europe's top economy, address the European Parliament against the backdrop of a debate over the current and future shape of the EU as it battles severe financial turbulence.
After reportedly predicting Saturday it would take "five years or more" to overcome the euro crisis, Merkel will lay out to deputies "her thoughts on the further development of the Economic and Monetary Union," her spokesman has said.
She will later travel to London for a working dinner with Cameron amid tension over the EU's long-term budget before a summit this month and a week after he suffered a parliamentary defeat over the issue.
Both stops are expected to provide Merkel an opportunity to highlight her credo – that the EU must work towards more integration especially on member states' budgetary issues as a way out of its crisis.
But Germany's push for ever-greater coordination may well fall on deaf ears during her visit to Britain, which is a member of the EU but is outside the 17-nation eurozone.
"The coalition government is committed to Britain playing a leading role in the EU but I must also be frank: public disillusionment with the EU in our country is the deepest it has ever been," Foreign Secretary William Hague told a foreign policy forum in Berlin last month.
His comments contrasted sharply with remarks by his German counterpart who said Berlin's drive for a fiscal union imposing budgetary discipline – which Britain has declined to join, and EU plans for a banking union were part of a crucial integration process that would benefit all.
The "disillusionment" translated last week into a defeat for Cameron when rebels from his Conservative party defied him by passing a motion urging him to insist on a real-terms cut in the EU's 2014-2020 budget.
Cameron says that a seven-year EU budget freeze in real terms is the best Britain can realistically expect, as most member states support a boost.
Merkel said after talks with Irish Prime Minister Enda Kenny last week that Germany would do "everything in its power to try to achieve a solution" in the negotiations on the budget.
A summit is due to be held on November 22 and 23 to hash out a deal.
"We are in a phase of intensive discussions, that is one of the reasons why [Merkel] is travelling to London to see Mr Cameron for talks," spokesman Steffen Seibert told reporters.
"Our views on the long-term financial planning and those laid out in recent weeks by the British government aren't that far apart," he said.
Olaf Boehnke, of the European Council on Foreign Relations, said Merkel's trip to London "may be interpreted as a wake-up call for the British" over the risks of distancing themselves from the EU.
Britain's relationship with Europe provoked EU Commissioner for Financial Programming and Budget Janusz Lewandowski to suggest in Friday's Süddeutsche Zeitung newspaper that Britain faced a choice.
"Either it [Britain] sees its long-term future in the European Union, or this isn't the case," he said.
And the head of the Greens party in the European Parliament Daniel Cohn-Bendit has even called for a referendum in Britain to decide whether it "becomes the 51st state of the United States" or if it is part of the EU.
In Berlin however the tone remains more conciliatory. Britain is "a member of the European Union that we hold in high regard," Seibert stressed recently, citing its free trade, entrepreneurship and economy.